Electrical troubleshooting

[04silversnake]

This is in the 91 gt. Probably someone can help me. When the car is running the voltage is close to the middle and the engine temperature is about 1/4 closed to the cool position at the cluster. Once I turn on the lights, A/C fan specially in hi, or any other accessories, I notice that the temperature gauge goes slightly above the middle, The more accessories I have on, the higher it goes. Now, this is not the real temperature of the coolant, I know this because if I turn off the car and restart it with lights, A/C off, the gauge goes back to 1/4. It looks like the temp gauge is affected by voltage as well. I know is not as good as having an aftermarket gauge. Also, the courtesy light gets a little dim. My question is, is there a problem with a cable that is too small for the current drawn that goes to the fuse box, and if it can be replaced for a thicker (smaller gauge) cable. Do you guys have experience this?
Any help is appreciated.
Franck

 

[93Cobra#2771]

With an electric fan that has any pull, you are most likely over taxing your stock alternator. However, you need to put a voltmeter on the battery terminals to see what your exact voltage is during the condition...

 

[04silversnake]

With an electric fan that has any pull, you are most likely over taxing your stock alternator. However, you need to put a voltmeter on the battery terminals to see what your exact voltage is during the condition...

I am running the stock fan clutch. I measured voltage at the battery terminal and it was fine, if I recall correctly it was close to 13 volt. but when I measured the voltage at the fues box, I got 12.xx on the fuses that are hot at all times, but voltage was low at the fues that are hot with ignition like 11.7x volts.

 

[93Cobra#2771]

You should actually have a high 13v or low 14v at the battery.

When you said fan, I thought you meant electric fan - my mistake. Do you have underdrive pullies on the car? Also, you need to check your ground cable for damage/corrosion...

 

[04silversnake]

You should actually have a high 13v or low 14v at the battery.

When you said fan, I thought you meant electric fan - my mistake. Do you have underdrive pullies on the car? Also, you need to check your ground cable for damage/corrosion...

No problem, I was refering to the A/C fan. I dont have underdrive pullies. The ground cable looks fine. :shrug:
Also, The voltage at the battery may have been somewhere in the high 13 or low 14. I think that is what I measured. Just did not recall for sure.

 

[BADBOYSPACK]

My 92 GT did near the same thing, when i turned on the headlight i could watch the oem tepm gauge go up a little, and when i turned them off i could see the gauge go back down. Then later the alt light would come on from time to time but the volts were fine. I bet it was a ground issuue, but I wrecked the car before i found out what was wrong

 

[04silversnake]

My 92 GT did near the same thing, when i turned on the headlight i could watch the oem tepm gauge go up a little, and when i turned them off i could see the gauge go back down. Then later the alt light would come on from time to time but the volts were fine. I bet it was a ground issuue, but I wrecked the car before i found out what was wrong

That is what my car does, except that my alternator light does not comes on. I will check or replace the ground cable. Even though it does not look bad, it may need replacement.

 

[BADBOYSPACK]

That is what my car does, except that my alternator light does not comes on. I will check or replace the ground cable. Even though it does not look bad, it may need replacement.

Just clean the connection under the cable,and the cable itself with a wire brush or sandpaper, dont waste you money just yet.

Mt alt light didnt start coming on till the last 2 months or so before it got wrecked, but the damn temp gauge did it for about a year before the wreck

 

[04silversnake]

Just clean the connection under the cable,and the cable itself with a wire brush or sandpaper, dont waste you money just yet.

Mt alt light didnt start coming on till the last 2 months or so before it got wrecked, but the damn temp gauge did it for about a year before the wreck

Ok, I will try cleaning the contact surface with a wire brush, and take it from there.
Thank you all for the replies,
Franck

 

[BADBOYSPACK]

Y/W silversnake