Electrical frustration!! Expert help needed!! (long)
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Electrical frustration!! Expert help needed!! (long)
OK it's a long story but here it is: I have an '89 Coupe that has what I assume is an electrical short...somewhere. It keeps blowing the 10 amp "GAUGES" fuse when it hits a bump in the road, not every bump just particular size bumps at particular speeds. And after 2 years with this problem, I have narrowed it down to happening only when the radio and AC are on together...or so it seems.
I have spent many hours tracing wires, grounds, junctions etc...no luck. I have PAID 2 mechanics and one Chevy dealer and gotten misdiagnosis' or plain befuddlement from them.
I have checked the "normal" spots for this fuse i.e. sunvisor lead, headlights, front loom on right of engine...no luck.
I thought I had it licked because it hadn't happened all winter, the yesterday while riding w/ radio and air on it blew when I went over RR track.
Please, if anyone has any SERIOUS advice I would greatly appreciate it. When it goes the ABS light comes on, the radio and AC go off, the headlights go out and the alt. doesn't charge( I've replaced that 3 times due to mechanic's guesses.)
Thanks
I have spent many hours tracing wires, grounds, junctions etc...no luck. I have PAID 2 mechanics and one Chevy dealer and gotten misdiagnosis' or plain befuddlement from them.
I have checked the "normal" spots for this fuse i.e. sunvisor lead, headlights, front loom on right of engine...no luck.
I thought I had it licked because it hadn't happened all winter, the yesterday while riding w/ radio and air on it blew when I went over RR track.
Please, if anyone has any SERIOUS advice I would greatly appreciate it. When it goes the ABS light comes on, the radio and AC go off, the headlights go out and the alt. doesn't charge( I've replaced that 3 times due to mechanic's guesses.)
Thanks
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
If you owned the electrical diagnosis manual for your car you would find out that the gages fuse supplies power to 18 devices in your car(I have an 87 and assume the 89 is similar). You will need to trace the 12v wires from this fuse to each device and inspect for abraded insulation or a pinched wire that touches ground when it is shaken hard from the bump you run over. NOT EASY!
Another way to find it is to put an inline fuse of less than 10 amps in each of the 18 wires from the gages fuse and observe which one blows at the next event. MUCH EASIER THAN TRACING 18 WIRES!
In my opinion, the radio and the a/c have nothing to do with your problem.
Another way to find it is to put an inline fuse of less than 10 amps in each of the 18 wires from the gages fuse and observe which one blows at the next event. MUCH EASIER THAN TRACING 18 WIRES!
In my opinion, the radio and the a/c have nothing to do with your problem.
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
"In my opinion, the radio and the a/c have nothing to do with your problem."....
You may be right, but it has absolutely only happened when BOTH of these were on. I guess it could be coincidence.
"MUCH EASIER THAN TRACING 18 WIRES!"... "easier" in this case is relative. Also, this is my daily driver. Can anyone help me hone in more specifically based on a similar problem they had?
Thanks jfb.
You may be right, but it has absolutely only happened when BOTH of these were on. I guess it could be coincidence.
"MUCH EASIER THAN TRACING 18 WIRES!"... "easier" in this case is relative. Also, this is my daily driver. Can anyone help me hone in more specifically based on a similar problem they had?
Thanks jfb.
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
You may be in luck! Several years ago I went through the same thing (except paying someone to fix it) and I was able to trace the short back to the EGR solenoid connector, it was shorting out internally and blowing the gauge's fuse. Changed the connector and nary a problem since.
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
Originally Posted by Phantom90
An EGR seliniod connector what in the horse poop is that? You wouldnt have a pic of it or maybe be able to tell me what page in the Helm manual it is on would you 
The EGR solenoid is "usually" mounted to the intake manifold, RH rear corner. It is a 2 pin connector, pink & black wires and has 2 hard plastic vacuum lines going to it.
Instructor
Joined: Apr 2001
Posts: 101
Likes: 0
From: Hyvinkaa Finland
If this help anybody, please download the whole "1990 Section 8A Electrical Diagnosis Service Manual Supplement" from my page. I have scanned all 468 pages with good resolution.
You can download it from:
http://www.hyke.fi/moisio/1990corvette.rar
Pictures are in jpg. 140Mb.
Gauges fuse: pic 8A-11-09.JPG
You can download it from:
http://www.hyke.fi/moisio/1990corvette.rar
Pictures are in jpg. 140Mb.
Gauges fuse: pic 8A-11-09.JPG
Last edited by Rokka; Jul 16, 2005 at 05:31 AM.
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Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Phantom 90: Mine is located on the front left of my int. man., it's at the end of the plastic line that comes out of the EGR. I checked mine out and it looks good however I didn't unwrap it where it goes into the harness that runs along the valve cover.
Rokka, thanks alot. I'll check the manual and see if it gets me anywhere. I really appreciate the effort.
I was hoping somebody might come up with a solution from an area I haven't investigated yet.
Thanks for all the responses.
Rokka, thanks alot. I'll check the manual and see if it gets me anywhere. I really appreciate the effort.
I was hoping somebody might come up with a solution from an area I haven't investigated yet.
Thanks for all the responses.
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
Originally Posted by joseph p
Phantom 90: Mine is located on the front left of my int. man., it's at the end of the plastic line that comes out of the EGR. I checked mine out and it looks good however I didn't unwrap it where it goes into the harness that runs along the valve cover.
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Morley: So you took the harness and opened it all up? I was thinking that the abrasion might only be possible at the points outside of the harness. I'm very tempted to try this because thinking back to when I took the manifold off because of a blown intake gasket, just after that was the beginning of blown gauges' fuses. Maybe I moved something!
I can't try that today, but I may do it tomorrow.
Thanks, again.
I can't try that today, but I may do it tomorrow.
Thanks, again.
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
Originally Posted by joseph p
Morley: So you took the harness and opened it all up?
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Where does the other end connect to?
Duh.....I get it , you're saying that your plug connector was the culprit and you just replaced the plug! I'll check that out and hope it's a visible problem. I thought you were saying it was in the wiring further down.
Sorry for the confusion...must be alzheimers again.
Thanks
Duh.....I get it , you're saying that your plug connector was the culprit and you just replaced the plug! I'll check that out and hope it's a visible problem. I thought you were saying it was in the wiring further down.
Sorry for the confusion...must be alzheimers again.
Thanks
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Well, it was encouraging for a little while. I checked the EGR connector and wires, and all look fine. Kinda knew with my luck it wouldn't be that simple.
Still believing radio and AC are not just coincidental. Just won't blow fuse without both of them on.....
Anyone?
Still believing radio and AC are not just coincidental. Just won't blow fuse without both of them on.....
Anyone?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Radio isn't on the circuit (unless someone added an aftermarket unit and spliced into it for power). If no one has dug into the dash, I'd be more suspicious about the engine compartment. Doubt it's the EGR solenoid, because if you lost this at cruise, it should generate a Trouble Code. I'd look at the Air Pump Solenoid (for which there are no codes)It's spliced into the EGR circuit and since it isn't spitting out a 32, you will only have to trace the wires (Pink/Black) from the connectors up to the splice. The only other engine compartment item would be the fuel canister solenoid over in the left headlight fender well. There's a couple of sharp bolts over there (I've cut my hand on a few), so you might want to look there too. That line is separate from the EGR/Air Pump Circuit terminating at Pin D5 at C100 - the big connector behind the battery. The EGR/Air Pump is at Pin G2. If you don't find the problem at the Air Pump or the Canister Solenoids, you could look at the harness at this connector, but I'd rule out G2 because you aren't getting the 32.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
I believe the '90 has a different EGR circuit or means of generating the 32. I did take a look at the A/C Control Panel 32 Pin connector. All of the wires next to the gages input are low voltage outputs. If the connector was the problem, you'd probably have damage to the Blower Module, High/Lo Pressure Switches or maybe the Programmer. Since the a/c continues to work after you've replaced the fuse, I wouldn't suspect the a/c. That doesn't mean that there isn't some internal short in the assembly, but if you haven't had it out for some reason, I'd stick to poking around the engine compartment (if only because I operate on the principal that the last thing I fixed is the reason the next thing has broken!).
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,444
Likes: 4
From: Hawthorne NJ
Yes there is a different radio. And there are no codes ever showing.???
" I operate on the principal that the last thing I fixed is the reason the next thing has broken!".....
If that's the case, the manifold gasket leak was probably the last, which touched in ALL the areas you're mentioning.
The car has an ALPINE stereo which had 24+ speakers, a subwoofer box, and two amps. I removed most of them so I could have some bask deck storage area. I checked those wires as best I could a year before the manifold work, when I first got the car.
" I operate on the principal that the last thing I fixed is the reason the next thing has broken!".....
If that's the case, the manifold gasket leak was probably the last, which touched in ALL the areas you're mentioning.
The car has an ALPINE stereo which had 24+ speakers, a subwoofer box, and two amps. I removed most of them so I could have some bask deck storage area. I checked those wires as best I could a year before the manifold work, when I first got the car.
Last edited by joseph p; Jul 18, 2005 at 11:18 PM.