Got rid of "useless" wires in harness....now no power to anything
03-07-2015, 02:48 PM
#1
Le Mans Master
Thread Starter
Got rid of "useless" wires in harness....now no power to anything
So I may have gotten a little carried away removing wires from my dash and engine harness. It started out simple with things like AIR pump and windeshield washer pump wiring. Then I got into the dash harness and completely removed VATS wiring and theft deterrent wiring. VATS programming disabled via tuning program.
Now I don't have power to anything, even items that should be hot at all times without ignition on. Ignition switches are brand new and worked fine before I started going wire stripping crazy. I still have all the wiring, so most of it can be reversed but wondering what the heck I goofed up...
Major systems entirely removed from harness:
VATS and associated wiring (but starter enable relay still in place)
Anti theft system (planned replacement with aftermarket)
Electronic Air Conditioning
Circuit breaker wiring to fuse block except power window breaker
Courtesy delay timer and associated wiring
Basically, I just wanted the bare minimum to start and run the car. At this point I'm probably going to "reset" and just get another engine and dash harness but this one is bugging me. Any ideas? Definitely learned my lesson on this one....don't touch anything. So much for starting the 383 this weekend.
Now I don't have power to anything, even items that should be hot at all times without ignition on. Ignition switches are brand new and worked fine before I started going wire stripping crazy. I still have all the wiring, so most of it can be reversed but wondering what the heck I goofed up...
Major systems entirely removed from harness:
VATS and associated wiring (but starter enable relay still in place)
Anti theft system (planned replacement with aftermarket)
Electronic Air Conditioning
Circuit breaker wiring to fuse block except power window breaker
Courtesy delay timer and associated wiring
Basically, I just wanted the bare minimum to start and run the car. At this point I'm probably going to "reset" and just get another engine and dash harness but this one is bugging me. Any ideas? Definitely learned my lesson on this one....don't touch anything. So much for starting the 383 this weekend.
Last edited by 1985 Corvette; 03-07-2015 at 02:50 PM.
03-07-2015, 04:32 PM
#2
Melting Slicks
Gee, ya think? 
Kinda hard to help when you're so far off the 'path', but all you need is the starter main feed, the solenoid, 12VDC to the HEI and FP, right?
There may be harnesses already available for what you are doing. I got one for another project with all new plugs and bypasses of unused circuits, but it was FoMoCo, for Cobra builders. That was definitely worth $500!
the harness in my car was redone by Jim's Performance in Ellicott City, VA.; sharp guy and very helpful.
Kinda hard to help when you're so far off the 'path', but all you need is the starter main feed, the solenoid, 12VDC to the HEI and FP, right?
There may be harnesses already available for what you are doing. I got one for another project with all new plugs and bypasses of unused circuits, but it was FoMoCo, for Cobra builders. That was definitely worth $500!
the harness in my car was redone by Jim's Performance in Ellicott City, VA.; sharp guy and very helpful.
03-07-2015, 06:08 PM
#3
Safety Car
I have a '85 F body engine harness if it helps. I know you changed to the '86 but it might help except for the ECM. I have the Helms version of the '85 FSM but it doesnt have the wiring diagrams just an elementary item and color codes running to it. What you have done bneeds the full wiring diagram and you will need one for an '86 probly. I did the same procedure with a '90 Jeep and stripped out all the extra wiring for the ECM and associated sensors but my results were better than yours I guess.
You are going to have to get the '86 diagrams and look to see what primary feed wires are involved. Cliff has an '86 and Agent 86 as well. Doesnt Vader have an '86? All of his stuff is posted on line so that might be a good source if you dont have any '86 related diagrams. If you had power to the always on stuff I would look at the ignition relayed wiring. Have you verified that your grounds have been re-established? The other side of the coin ya know.
I can come over and help. Just give me a call or shoot a text and I will see if I can spot something.
Good luck!
You are going to have to get the '86 diagrams and look to see what primary feed wires are involved. Cliff has an '86 and Agent 86 as well. Doesnt Vader have an '86? All of his stuff is posted on line so that might be a good source if you dont have any '86 related diagrams. If you had power to the always on stuff I would look at the ignition relayed wiring. Have you verified that your grounds have been re-established? The other side of the coin ya know.
I can come over and help. Just give me a call or shoot a text and I will see if I can spot something.
Good luck!
03-07-2015, 07:12 PM
#4
Le Mans Master
Thread Starter
Gee, ya think?
Kinda hard to help when you're so far off the 'path', but all you need is the starter main feed, the solenoid, 12VDC to the HEI and FP, right?
There may be harnesses already available for what you are doing. I got one for another project with all new plugs and bypasses of unused circuits, but it was FoMoCo, for Cobra builders. That was definitely worth $500!
the harness in my car was redone by Jim's Performance in Ellicott City, VA.; sharp guy and very helpful.
Kinda hard to help when you're so far off the 'path', but all you need is the starter main feed, the solenoid, 12VDC to the HEI and FP, right?
There may be harnesses already available for what you are doing. I got one for another project with all new plugs and bypasses of unused circuits, but it was FoMoCo, for Cobra builders. That was definitely worth $500!
the harness in my car was redone by Jim's Performance in Ellicott City, VA.; sharp guy and very helpful.
Perhaps nothing an all nighter wire tracing can't figure out....
I have a '85 F body engine harness if it helps. I know you changed to the '86 but it might help except for the ECM. I have the Helms version of the '85 FSM but it doesnt have the wiring diagrams just an elementary item and color codes running to it. What you have done bneeds the full wiring diagram and you will need one for an '86 probly. I did the same procedure with a '90 Jeep and stripped out all the extra wiring for the ECM and associated sensors but my results were better than yours I guess.
You are going to have to get the '86 diagrams and look to see what primary feed wires are involved. Cliff has an '86 and Agent 86 as well. Doesnt Vader have an '86? All of his stuff is posted on line so that might be a good source if you dont have any '86 related diagrams. If you had power to the always on stuff I would look at the ignition relayed wiring. Have you verified that your grounds have been re-established? The other side of the coin ya know.
I can come over and help. Just give me a call or shoot a text and I will see if I can spot something.
Good luck!
You are going to have to get the '86 diagrams and look to see what primary feed wires are involved. Cliff has an '86 and Agent 86 as well. Doesnt Vader have an '86? All of his stuff is posted on line so that might be a good source if you dont have any '86 related diagrams. If you had power to the always on stuff I would look at the ignition relayed wiring. Have you verified that your grounds have been re-established? The other side of the coin ya know.
I can come over and help. Just give me a call or shoot a text and I will see if I can spot something.
Good luck!
Thanks, Steve, I may end up bugging Cliff. Small sparks at the battery terminals when I hook up the negative cable but no power to anything. I figure try tracing the ignition switch wiring down because turning the key to bulb test does nothing. You know me, I gotta counter the success threads with a good blunder topic from time to time.
03-08-2015, 12:10 AM
#5
Race Director
All the pink wires with black stripe should be "hot at all times". Check for 12 volts at the fuse block. You can probe the fuses without removing them, so that will make things easier.
Check out the fusible link diagram in section 8A of the FSM. In my '86 FSM it's page 8A-10-0, titled "Power Distribution". I know GM changed the page numbering system in the FSM but not when that happened, so that diagram may be somewhere else in your FSM.
Do you get 12 volts on the pink wire at the distributor when you turn on the ignition switch? It doesn't have to be plugged in to check this.
The ECM is powered all the time through fusible link H. The "ECM" fuse is for the connection between the ignition switch and the ECM. Probe that fuse with the ignition on to see if 12 volts is getting there.
Check out the fusible link diagram in section 8A of the FSM. In my '86 FSM it's page 8A-10-0, titled "Power Distribution". I know GM changed the page numbering system in the FSM but not when that happened, so that diagram may be somewhere else in your FSM.
Do you get 12 volts on the pink wire at the distributor when you turn on the ignition switch? It doesn't have to be plugged in to check this.
The ECM is powered all the time through fusible link H. The "ECM" fuse is for the connection between the ignition switch and the ECM. Probe that fuse with the ignition on to see if 12 volts is getting there.
03-08-2015, 01:34 AM
#6
Le Mans Master
Thread Starter
All the pink wires with black stripe should be "hot at all times". Check for 12 volts at the fuse block. You can probe the fuses without removing them, so that will make things easier.
Check out the fusible link diagram in section 8A of the FSM. In my '86 FSM it's page 8A-10-0, titled "Power Distribution". I know GM changed the page numbering system in the FSM but not when that happened, so that diagram may be somewhere else in your FSM.
Do you get 12 volts on the pink wire at the distributor when you turn on the ignition switch? It doesn't have to be plugged in to check this.
The ECM is powered all the time through fusible link H. The "ECM" fuse is for the connection between the ignition switch and the ECM. Probe that fuse with the ignition on to see if 12 volts is getting there.
Check out the fusible link diagram in section 8A of the FSM. In my '86 FSM it's page 8A-10-0, titled "Power Distribution". I know GM changed the page numbering system in the FSM but not when that happened, so that diagram may be somewhere else in your FSM.
Do you get 12 volts on the pink wire at the distributor when you turn on the ignition switch? It doesn't have to be plugged in to check this.
The ECM is powered all the time through fusible link H. The "ECM" fuse is for the connection between the ignition switch and the ECM. Probe that fuse with the ignition on to see if 12 volts is getting there.
03-08-2015, 08:31 AM
#7
If you have "NOTHING" you start first with the battery positive cable and it should have a lead attached to the "jump start junction block". All of the fusible links to the systems except ECM, horn and various years the AC originate there. If you've got the starter wired correctly with that fusible link in place then I'd think the horn should blow.
You don't need to go any further than the "POWER DISTRIBUTION " page and you need nothing more than a "test light".
If you have problems with "key-on" functions and other various symptoms then you need to likely start at the C100 bulk head connector.
You don't need to go any further than the "POWER DISTRIBUTION " page and you need nothing more than a "test light".
If you have problems with "key-on" functions and other various symptoms then you need to likely start at the C100 bulk head connector.
03-08-2015, 10:03 AM
#8
Drifting
Member Since: Dec 2007
Location: Sumter South Carolina
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I did the same project you did and went the extreme route also. I made some mistakes but tracked most easily (except one). What made things easier on me was moving to a push button start and race car ignition. Then I knew all my stuff was good since it was all new wiring. Making your own harness is simple and bypass all the stock stuff. The ac should work with just a power and ground and all other stuff still connected. Start simple though. Run a new power wire from bat to fuseable link. Then run straight to ignition from your column switch.
I would start taking a 12v positive wire and start stripping small pieces of wire you need powered and jumping it into them. If they work then you know that is the problem wire not getting power.
I would start taking a 12v positive wire and start stripping small pieces of wire you need powered and jumping it into them. If they work then you know that is the problem wire not getting power.
03-08-2015, 04:54 PM
#9
Le Mans Master
Thread Starter
Thanks for the advice guys. I did a little messing around with the ohmmeter and found a few things out.
1) All the orange wires on relays in the engine bay show 12.7 volts.
2) Junction terminal showing 12.7 volts
3) I have 12.7 volts as well off the red wires for left, right, and isolation relay for headlights.
3) Positive to starter connection registering 12.7 volts.
4) Fusible link directly off positive battery cable is 12.7 volts all the way through various connections using orange wires from the splice where many of them come together behind engine.
5) Unplugged ECM and B1 and C16 show 12.7 voltage as well from the orange wires.
6) No volts registered off pink w/ white stripe wire from distributor plug
7) Fuse block terminals measuring 0.01.....
85' and 89' FSM power distribution layouts I'm referencing...
1) All the orange wires on relays in the engine bay show 12.7 volts.
2) Junction terminal showing 12.7 volts
3) I have 12.7 volts as well off the red wires for left, right, and isolation relay for headlights.
3) Positive to starter connection registering 12.7 volts.
4) Fusible link directly off positive battery cable is 12.7 volts all the way through various connections using orange wires from the splice where many of them come together behind engine.
5) Unplugged ECM and B1 and C16 show 12.7 voltage as well from the orange wires.
6) No volts registered off pink w/ white stripe wire from distributor plug
7) Fuse block terminals measuring 0.01.....
85' and 89' FSM power distribution layouts I'm referencing...
Last edited by 1985 Corvette; 03-08-2015 at 04:57 PM.
03-08-2015, 07:30 PM
#10
At C100 bulk-head check A1 & B2 for 12V. I'm quite sure that should be consistent for all years.
Which fuses display no "supply" voltage?
Which fuses display no "supply" voltage?
Last edited by WVZR-1; 03-08-2015 at 07:33 PM.
03-08-2015, 08:37 PM
#11
Le Mans Master
Thread Starter
looking at this picture kind of jogged my memory. If I recall everything went though the oil pressure switch. I think I had to jumper that out.
I other words red and orange get connected at the oil pressure switch
if you want to leave your oil switch there then you need to make a temporary connection there. Not gospel, working from memory but it will give you a place to look.
I other words red and orange get connected at the oil pressure switch
if you want to leave your oil switch there then you need to make a temporary connection there. Not gospel, working from memory but it will give you a place to look.
One method of confirmation I didn't need: on the creeper checking voltage under car at the starter. Got my 12.7 I was looking for but accidentally touched the ground probe to the ground terminal and positive terminal making a nice blue and purple light show five inches from my face and the sound of a firecracker going off. Starter has voltage! Luckily I did not fry the fuse in the ohmmeter.
Will do. I called it quits for the day but it's like the voltage magically disappears on the other side of the firewall. I'll take another look but last probing displayed 0.01 (basically nothing) for the reading on the fuse block. There's also two auxiliary fuses from the 1986 wiring behind the dash that show nothing. Red wires in dash harness show nothing for reading even with key on. I'm confident I got wire strip happy and pulled out one too many "unneeded" wires at the fuse bulkhead.
Last edited by 1985 Corvette; 03-08-2015 at 08:43 PM.
03-08-2015, 09:40 PM
#12
Racer
get one of these---http://www.amazon.com/Power-Probe-PPR319FTCRED-Light-Voltmeter/dp/B005MVB3S0/ref=sr_1_5?s=automotive&ie=UTF8&qid=1425 865100&sr=1-5&keywords=power+probe check it on youtube
03-15-2015, 01:43 AM
#13
Le Mans Master
Thread Starter
Because race car, who needs grounds?
So this story of hilarity that only I could wallow into is forming a happy ending. It appeared I had two fusible links joined to one ring terminal and both had slipped out of the ring terminal but I did not know due to electrical tape covering the crimp. New ring terminal crimped on and I got my lights. I still couldn't get the dash to "turn on" despite having 12 volts to it and the turn signal bulbs flashing. It took me, sadly, all day to stumble across a ground in the FSM out of D3 to the cluster, which goes through C100 and joins other ring terminal grounds on the back of the driver side cylinder head. It was missing due to my desire to elimintate the electronic AC system from the harness, I observed the ambient air temp ground used B1 of C100 but failed to grasp the thought that the cluster was piggy backing a ground on this one as well to the engine.
Not only was it missing from C100 but I had eliminated the ground wire from the cluster plug. A+ build, would read again. Turn the key and I have a dash again....AND the audible chime actually chimes if you leave the lights on with the key in the off position, instead of a beep randomly every minute or so. Amazing what a simple ground will do. But I have no lights in the cluster lit, even when I flip the headlight switch. I did take the dash apart and I think the bulbs I'm using are not the correct ones. Can someone recommend a direct replacement that can be found at the local parts store?
"Hot at all times" fuses show 12 volts and other fuses show 12 volts when in "test" or "run" key position, so that's more rays of light. There is one fuse that shows nothing when probed and that is the "INST" 3 amp fuse. Maybe this is why I don't have dash cluster lights? I couldn't stare at it anymore for the night.
Edit: Anyone got a pic of their denso starter wiring wired up their starter? the FSM pic leaves a little to be desired.
Not only was it missing from C100 but I had eliminated the ground wire from the cluster plug. A+ build, would read again. Turn the key and I have a dash again....AND the audible chime actually chimes if you leave the lights on with the key in the off position, instead of a beep randomly every minute or so. Amazing what a simple ground will do. But I have no lights in the cluster lit, even when I flip the headlight switch. I did take the dash apart and I think the bulbs I'm using are not the correct ones. Can someone recommend a direct replacement that can be found at the local parts store?
"Hot at all times" fuses show 12 volts and other fuses show 12 volts when in "test" or "run" key position, so that's more rays of light. There is one fuse that shows nothing when probed and that is the "INST" 3 amp fuse. Maybe this is why I don't have dash cluster lights? I couldn't stare at it anymore for the night.
Edit: Anyone got a pic of their denso starter wiring wired up their starter? the FSM pic leaves a little to be desired.
Last edited by 1985 Corvette; 03-15-2015 at 01:49 AM.
03-15-2015, 07:54 PM
#14
Race Director
I wrote an article on early C4 dash backlighting which might be helpful (warning: lots of geeky technical stuff):
http://forums.corvetteforum.com/c4-t...ull-story.html
The executive summary of the power for the back lights: 12 volts comes from the ignition switch into pins J1-C16 and J1-D16. The ground for the back lights is on pin J1-D1. I don't know where it connects to ground offhand.
Last edited by Cliff Harris; 03-15-2015 at 08:04 PM.
03-15-2015, 08:30 PM
#15
Le Mans Master
Thread Starter
The bulbs depend on the year. #882 from '84 to '88. I don't know what they changed to in 1989, but it is a xenon vs. the earlier halogen bulbs and has a wedge base vs. the earlier pin base, so the sockets are different. The #882 comes with a socket. If you can find them, #882X is the same bulb without the socket. These bulbs had limited usage, so I think it would be hard to find them in the average auto parts store.
I wrote an article on early C4 dash backlighting which might be helpful (warning: lots of geeky technical stuff):
http://forums.corvetteforum.com/c4-t...ull-story.html
The executive summary of the power for the back lights: 12 volts comes from the ignition switch into pins J1-C16 and J1-D16. The ground for the back lights is on pin J1-D1. I don't know where it connects to ground offhand.
I wrote an article on early C4 dash backlighting which might be helpful (warning: lots of geeky technical stuff):
http://forums.corvetteforum.com/c4-t...ull-story.html
The executive summary of the power for the back lights: 12 volts comes from the ignition switch into pins J1-C16 and J1-D16. The ground for the back lights is on pin J1-D1. I don't know where it connects to ground offhand.
03-20-2015, 11:55 PM
#16
Le Mans Master
Thread Starter
Cliff Harris is the man!
I finally figured out my no light issue for the dash cluster. It ended up being a few of the pin connectors inside the dash which connect both circuit boards. I spent nearly five hours last weekend chasing wires, grounds, splices, and back probing contacts inside connections for voltage.....Cliff Harris figured it out in two PMs to me that probably took him a combined time of five minutes worth of typing. Where I started and where I ended up:
Re-skinned displays with polarizing film, this is probably when pins were damaged doing this project
Key on and although graphics display but no back lighting
Took it apart and went straight to what Cliff mentioned and found a clue
Hard to see but underside of board with tiny cracks from pin locations
Not the best solder job and was worried about cooking the board.
And we have lights again
Popped the dash back in, plugged it in, and said, "Nothing is ever this easy......not gonna work". Turned the key and got a nice surprise worth drinking a beer over. Thanks, Cliff.
Anybody got a pic of their Denso starter wired up?
Re-skinned displays with polarizing film, this is probably when pins were damaged doing this project
Key on and although graphics display but no back lighting
Took it apart and went straight to what Cliff mentioned and found a clue
Hard to see but underside of board with tiny cracks from pin locations
Not the best solder job and was worried about cooking the board.
And we have lights again
Popped the dash back in, plugged it in, and said, "Nothing is ever this easy......not gonna work". Turned the key and got a nice surprise worth drinking a beer over. Thanks, Cliff.
Anybody got a pic of their Denso starter wired up?