Expert: Rob Painter - 4/6/2011

Question
QUESTION: Hi i have a 1994 Cadillac eldorado, i was in the stereo area and hooked the purple with white stripe, orange with black stripe and black with orange stripe to 12v, i replaced the ipc and now the fuel gauge, retained power accessory and turn signals don't work. also the change tranny fluid message is stuck on and will not clear.All grounds are in contact, all fuses are good  i also replaced the turn signal flasher to no avail. I have also done my best to trace the wires and look for a burned wire or a spot where its grounding, i have not gone to look at the bcm.

ANSWER: Hello,

Not sure what you did here and this is why they make radio wiring kits for about $12 if you were changing the stereo. You have more than one fuse box on the car and you need to look at your owners manual for locations.

What is throwing me off slightly is the retained power. That has a circuit breaker and not a fuse, but it may get power from a different source as well. Why did you change the instrument panel cluster and fuel gauge.

You don't say why you were in the stereo area either for changing out the stereo or who knows?

Orange and black has been commonly a cigarette lighter power, not saying it is for yours, but over the years GM commonly used that color code for that accessory.

Why would you hook power to wires that you don't even know what they go to? If you hook power to a power wire, you will end up with a feed back situation which could burn things up being most of these wiring systems are not protected by diodes to prevent feedback.

What exactly was your original problem that cause you to hook these wires to power and change the ipc and fuel gauge?

It is a standard rule to never hook 12v to a wire you have no idea as to what it is for. that is why a test light or a meter is used.

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---------- FOLLOW-UP ----------

QUESTION: The ipc started smoking and the display went out, thats why i changed it. I was trying to find my pink wire thats supposed to be the power antenna and was at accessory and connected up to those three wires, the stereo was put in before i got the car hence the cut wires and no harness. I went out today and its having starting problems and a TO72 popped up but only as history, also the change Trans fluid message will not reset i held rear defog and reset for several minutes all previous problems remain

ANSWER: Hello,

Here is what I was warned when serving as a tech for GM for 11 years. Never go by the color of the wire and only to follow circuits. At least that is what GM taught me. Over the years, I have learned this to be true so many times.
Right now you are chasing ghosts which commonly have a cascading effect. One part is changed only to have another fail.

A couple moths ago I received a question on this site about a charging system problem that had discharged to 9v and then spiked to 14v and then discharged again. The first mechanic told him it was the alternator. He had the alternator changed. After driving for a couple of weeks, the problem arose again. He took the car to the dealer. They found a bad gauge unit. Problem happened again and dealer found a bad bcm. A couple more weeks, problems again and this time his new battery he had recently installed was fried.
He said all wiring had been checked, but I explained in his case that it was a very simple system as it relates to charging and told him all these things burning out related to the same underlying problem and it was just not possible that all these things could just go bad on their own. I told him to check the grounds at the battery and charging system. The mechanic he had looking at the wiring removed and repositioned the battery ground by about 6."
That was then end of any charging system problems.
What got me here is that everyone was just changing parts and not putting the whole story together. If they could have, they could have saved this guy $1,300 in replacement of parts.
The spike in voltage on all these different occasions, burn't up the charge gauge. The next time, the bcm and yet the next time, the new battery and all because not any of these mechanics put this all together and because of their incompetence, this guy spent a lot of money!
Because I told this guy what to take into consideration and to check the grounds, the problem was now fixed!
I only give this story as an example as to what you are running into. Its the chicken/egg syndrome.

I appreciate people trying to fix their own cars, especially after this story I gave you and the owner would have probably done better than these so-called technicians.
The only issue is that you can't do this without the tools. No, I am not talking about a lot of money. A cheap test light or meter and you have to have the factory service manual with schematics and diagnoses. You are working in the blind on a computer operated car and all you are going to do without a manual is waste more time and a lot of money with new problems popping up!

Personally, I do no diagnostics or repair without the factory manual information at my disposal. Look at the grief your are going through much less the money!
go to http://www.alldata.com and scroll for your make and model. Pay the $30 membership fee and download the complete factory manual for a year. Once you see what is in the manual, you will be asking why you didn't do this before.

This information will assist you in repairing the problems you have for good and will take out all the guesswork.

Let me know what you found to be the problem.

Good Luck!

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---------- FOLLOW-UP ----------

QUESTION: I went to the site provided and paid, got through and found that one of my grounds is hot/ has power when the car is off, when i pulled the ground it sparked and caused the heater blower to come on, when cleaned and replaced the heater went off, what causes a ground to get power, and how would i fix it? thank you so much for all youve done so far!

Answer
Hello,

Feedback will cause this, but the question is where is the feedback coming from? As I stated before, it could be a cascading effect and to say exactly what the cause without being physically at the car, it would be irresponsible for me to guess.

Your grounds should never have power and until you find out why this is happening, you should disconnect the grounds, because you can just burn something else up.

What exactly was the original complaint? What caused you to change the IP and the fuel gauge in the first place?

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