alternator charging and wiring issues
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
alternator charging and wiring issues
Hey guys. Looking for a little information about the wiring on my 79. According to the wiring diagram I have there's a red power wire that runs from starter terminal, through firewall bulkhead (terminal 2), splits out into 4 other wires. 1 wire runs back through the bulkhead to the alternator, 2 go to the ignition switch, and 1 goes to the fuse box.
I'm hoping someone might know the location of this point where the wires split out to each equipment which would make my life easier if I don't have to pull the dash! My issue is something on this circuit shows to be grounded out when I check the continuity/ohms of the wire to frame/ground.
A little information. ....car is a 1979. I added a cs144 and is correctly wired with 4ga charge wire to starter terminal and resistor in line because i dont have the gen light. Whith the car running and nothing else on (no headlights, elec fans, etc) my meter reads 75amps on the charge wire going back to the starter and then to the battery. Which leads me to a wire being grounded, see paragraph uptop.
Thanks for any help, sorry for post being long but background helps with electrical stuff.
Ryan
I'm hoping someone might know the location of this point where the wires split out to each equipment which would make my life easier if I don't have to pull the dash! My issue is something on this circuit shows to be grounded out when I check the continuity/ohms of the wire to frame/ground.
A little information. ....car is a 1979. I added a cs144 and is correctly wired with 4ga charge wire to starter terminal and resistor in line because i dont have the gen light. Whith the car running and nothing else on (no headlights, elec fans, etc) my meter reads 75amps on the charge wire going back to the starter and then to the battery. Which leads me to a wire being grounded, see paragraph uptop.
Thanks for any help, sorry for post being long but background helps with electrical stuff.
Ryan
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Well your small red wire to the starter solenoid splits into 3 wires - not 4 - at the starter harness. One wire goes through pin #2 of the bulkhead/firewall connector to the "hot" junction inside the pass compartment under the dash - which in turn loops back and connects to the alternator red "hot" wire on term "B". All the "hot loads" (ign sw, light sw, etc) are powered from the junction block under the dash.
Im suspecting the junction block for the red wires will be on the fuse block - but maybe not. Anyways it shouldn't be to hard to find with 4 red wires connected to it - unless its under the bundle wrap ( not likely). I dont see any fuse in any of these "hot" red wires.
Some thing u can do is lift one wire at a time and measure your alt current - and direction.
The 2C term on the bulkhead connector passes the red wire from starter to alternator term #2 (or alt to starter whichever way u look). This would be the charging source for your batt.
Hope this helps and ill look again at my chiltons once i get home (used an internet dwg for a '79 C3).
Im suspecting the junction block for the red wires will be on the fuse block - but maybe not. Anyways it shouldn't be to hard to find with 4 red wires connected to it - unless its under the bundle wrap ( not likely). I dont see any fuse in any of these "hot" red wires.
Some thing u can do is lift one wire at a time and measure your alt current - and direction.
The 2C term on the bulkhead connector passes the red wire from starter to alternator term #2 (or alt to starter whichever way u look). This would be the charging source for your batt.
Hope this helps and ill look again at my chiltons once i get home (used an internet dwg for a '79 C3).
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
OK chiltons has a better diag. Junction under dash has 6 red wires. Dont see where they meet though. U may have to look at where they terminate.
2 red wires go to ign sw = bat3 and bat2
2 red wires go to fuse block = STOP HAZ 20A, CTSY CLK 20A
1 red wire to upper firewall block #2A
1 red wire to lower firewall block #2E
The 2C red wire goes to the "V" term on the alt per chiltons. Where that is on a CS144 only u would know.
2 red wires go to ign sw = bat3 and bat2
2 red wires go to fuse block = STOP HAZ 20A, CTSY CLK 20A
1 red wire to upper firewall block #2A
1 red wire to lower firewall block #2E
The 2C red wire goes to the "V" term on the alt per chiltons. Where that is on a CS144 only u would know.
Last edited by cardo0; Sep 9, 2014 at 02:45 AM. Reason: add last sentance.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
I'd expect the wires to all terminate in the the fuse block on the strip that provides battery power to the different parts of the block. It'll make more sense once you see it. There is a bar that provides power to the battery powered fuses and terminals on the front of the block and also has the wires going off the back to feed power to the different locations.
I do find it hard to believe that 75A would be a direct short. You should find part of the harness is smoking hot if that is the case. I can't say what device would draw 75A in the car though. Nothing that is working would but maybe something that has failed could. Still, whatever it is should be getting quite hot.
I do find it hard to believe that 75A would be a direct short. You should find part of the harness is smoking hot if that is the case. I can't say what device would draw 75A in the car though. Nothing that is working would but maybe something that has failed could. Still, whatever it is should be getting quite hot.
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
I haven't had much time to go through this thing yet. Here's what I've found though.
The splice point is actually in that main bundle of cables just to the left of the steering column. I had to pull back some of the wrapping to find the splice. I also went ahead and pulled down the fuse box so I could see exactly what's going on.
I think I traced one of the shorts down to a junkyard rearview mirror w/map lights & auto dim I put in a few years ago. I didn't have time to double check, I just unplugged and my meter no longer shows continuity to ground on that wire.
Since the fuse block is down I went ahead and tested the rest of the circuits. Looks like the pink wires with the splices are grounded too. Doesn't look like they should be a return or negative wire. I also noticed a smaller pink/black wire that was showing ground. Looks to be an ignition power source that has multiple taps on the fuse block.
Here's some pics. the 107amp reading was with my fans on. the 75amp was with them off.
photos of splices for anyone looking for them in the future.
80a fuse that was inline with the 4ga charge wire from the alt to the starter lug.
The splice point is actually in that main bundle of cables just to the left of the steering column. I had to pull back some of the wrapping to find the splice. I also went ahead and pulled down the fuse box so I could see exactly what's going on.
I think I traced one of the shorts down to a junkyard rearview mirror w/map lights & auto dim I put in a few years ago. I didn't have time to double check, I just unplugged and my meter no longer shows continuity to ground on that wire.
Since the fuse block is down I went ahead and tested the rest of the circuits. Looks like the pink wires with the splices are grounded too. Doesn't look like they should be a return or negative wire. I also noticed a smaller pink/black wire that was showing ground. Looks to be an ignition power source that has multiple taps on the fuse block.
Here's some pics. the 107amp reading was with my fans on. the 75amp was with them off.
photos of splices for anyone looking for them in the future.
80a fuse that was inline with the 4ga charge wire from the alt to the starter lug.
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
That's with the ford focus fans on and car running, no other accessories. Shows 107.5A set on DC voltage. You can see the setting on the **** set to DC --- current. It was showing 75A with fans turned off.
Race Director
Joined: Apr 2007
Posts: 11,152
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From: South Western Ontario
Interesting they had a big splice.
You do realize that any wire that powers a component will show continuity to ground? It won't be a direct short but it will be the resistance the component has.
75A goes into the cockpit on the original 10 gauge wire? I just find that hard to believe. It appears you're actually reading 75A (107A) on the new charging wire. How long did the car run when you measured that and how well was the battery charged?
Can you give some info on how you connected the rest of the wiring.
The current capability of that alternator is why a 80A fuse on the alternator charging wire Just isn't a good idea.
You do realize that any wire that powers a component will show continuity to ground? It won't be a direct short but it will be the resistance the component has.
75A goes into the cockpit on the original 10 gauge wire? I just find that hard to believe. It appears you're actually reading 75A (107A) on the new charging wire. How long did the car run when you measured that and how well was the battery charged?
Can you give some info on how you connected the rest of the wiring.
The current capability of that alternator is why a 80A fuse on the alternator charging wire Just isn't a good idea.
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Melting Slicks
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
OK, the 75 amps is way too high and another 30 for the fans sounds right. You are measuring DC current. Can you attach the leads to the red and black terminal, switch the meter to DC volts and connect the red to 12 volts and the black to ground and let me know what it reads? It is acting like the alternator is not sensing any output voltage and trying to run full out.
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
Interesting they had a big splice.
You do realize that any wire that powers a component will show continuity to ground? It won't be a direct short but it will be the resistance the component has.
75A goes into the cockpit on the original 10 gauge wire? I just find that hard to believe. It appears you're actually reading 75A (107A) on the new charging wire. How long did the car run when you measured that and how well was the battery charged?
Can you give some info on how you connected the rest of the wiring.
The current capability of that alternator is why a 80A fuse on the alternator charging wire Just isn't a good idea.
You do realize that any wire that powers a component will show continuity to ground? It won't be a direct short but it will be the resistance the component has.
75A goes into the cockpit on the original 10 gauge wire? I just find that hard to believe. It appears you're actually reading 75A (107A) on the new charging wire. How long did the car run when you measured that and how well was the battery charged?
Can you give some info on how you connected the rest of the wiring.
The current capability of that alternator is why a 80A fuse on the alternator charging wire Just isn't a good idea.
I only pulled the amperage on my 4ga wire going from the alternator to the starter terminal. Battery showed 11+ volts when I cranked it, didn't have any trouble cranking at all. (my engine has a little more compression than from the factory). Alternator ran for maybe minute or 2 before the fuse blew.
I have the alternator wired per the diagrams found on this site and matches other sites on the net along with the wiring diagram that came with the alternator. I have a resistor inline (330ohm I believe) from the gen light.(brown wire from interior, I have no gen night, I connected brown wire to ignition switch power behind the gauges as wiring diagram shows). I'll try to take a picture of the diagram and post for ya'll.
I didn't plan on running a 80a fuse forever, just to get it running......who would've thought it'd draw that much amperage with nothing else turned on in the car?.....
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
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2020 C3 of the Year Finalist - Modified
OK, the 75 amps is way too high and another 30 for the fans sounds right. You are measuring DC current. Can you attach the leads to the red and black terminal, switch the meter to DC volts and connect the red to 12 volts and the black to ground and let me know what it reads? It is acting like the alternator is not sensing any output voltage and trying to run full out.
Melting Slicks
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
If the 14 volts is correct, I don't trust the factory gauge, then that is about where you should be. I am not sure what could be drawing 75 amps, unless your battery has a very low charge. You could try pulling fuses 1 at a time until that load goes away, but I doubt you have any fuses that are 75 amps or more.
Race Director
Joined: Apr 2007
Posts: 11,152
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From: South Western Ontario
I'm not sure what's up with your ohmmeter, but a direct short would draw very high currents. Anything fused would blow the fuse immediately and any shorted wiring un-fused would start melting (hopefully the fusible link protects you). You'd also get a huge spark when you tried to connect the battery.
Even 75A would create a large spark when connecting the battery and then kill the battery within a few hours of it being connected. It just doesn't make sense to have that kind of current draw to the cockpit of the car without something starting on fire.
You did hold the DCA zero button until the display went to 0 first before measuring the current?
Does everything appear to work inside the car?
Even 75A would create a large spark when connecting the battery and then kill the battery within a few hours of it being connected. It just doesn't make sense to have that kind of current draw to the cockpit of the car without something starting on fire.
You did hold the DCA zero button until the display went to 0 first before measuring the current?
Does everything appear to work inside the car?
Thread Starter
Drifting
Joined: Nov 2004
Posts: 1,631
Likes: 293
2020 C3 of the Year Finalist - Modified
None of the fuse block wires or wires I tested showed a direct ground to frame. I did clear the other which went back to my rear view mirror. I cranked it after that and it was reading 93amps on the output wire of my alternator. Still high, but better than 107a. I'm going to crank the car and pull fuses to see if the amp load will drop will it's running. If there is a better way to trace down this short/load on the system please let me know.
Thanks for the help.
Thanks for the help.
Melting Slicks
Joined: Mar 2008
Posts: 2,989
Likes: 198
From: Meriden CT
I'm not sure what's up with your ohmmeter, but a direct short would draw very high currents. Anything fused would blow the fuse immediately and any shorted wiring un-fused would start melting (hopefully the fusible link protects you). You'd also get a huge spark when you tried to connect the battery.
Even 75A would create a large spark when connecting the battery and then kill the battery within a few hours of it being connected. It just doesn't make sense to have that kind of current draw to the cockpit of the car without something starting on fire.
You did hold the DCA zero button until the display went to 0 first before measuring the current?
Does everything appear to work inside the car?
Even 75A would create a large spark when connecting the battery and then kill the battery within a few hours of it being connected. It just doesn't make sense to have that kind of current draw to the cockpit of the car without something starting on fire.
You did hold the DCA zero button until the display went to 0 first before measuring the current?
Does everything appear to work inside the car?
