Thread: Ghosts in the System

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Hey guys. I have a real issue today, and since i cant figure it out, maybe you guys will give me a clue. Sitting in my driveway is this big blue thing of a caddy. Three days ago, it registered a short in the throttle position sensor circut/map circut/baro circut. After running down all three leads, i found that the TPS needed a change. Did that tonight, Nice improvement. However, now the blower motor comes on 24/7, even when the ignition is shut off. The blower motor isnt supposed to do that. Quite simply, im getting sick of having to work on this car. Other than having to tear out the entire climate controll and finding the solonoids responsable, has any one had this type of problem before? Any tips would be nice. The car is an 82 deville with Electronic climate controll and an efi 4100.

SELL IT FAST.............


I had a similar troubles with a 79 coupe de ville, one night about 2am the horn starts blowing so I go pull the battery cable.

Anyway after LOTS of hunting I found the foam rubber that is on the printed circut board to keep the horn cover (in this case) or buttons from making contact and completeing the circut was broken down and brittle and stopped doing it's job of holding the two apart ( hope that makes sence ) I cleaned off all that was left and found some foam that was close to the same and fabbed it back together.

So if your climate controls have that type of switching you might want to check it out.

Originally posted by drg84
Hey guys. I have a real issue today, and since i cant figure it out, maybe you guys will give me a clue. Sitting in my driveway is this big blue thing of a caddy. Three days ago, it registered a short in the throttle position sensor circut/map circut/baro circut. After running down all three leads, i found that the TPS needed a change. Did that tonight, Nice improvement. However, now the blower motor comes on 24/7, even when the ignition is shut off. The blower motor isnt supposed to do that. Quite simply, im getting sick of having to work on this car. Other than having to tear out the entire climate controll and finding the solonoids responsable, has any one had this type of problem before? Any tips would be nice. The car is an 82 deville with Electronic climate controll and an efi 4100.

how did you keep that 4100 runing that long drg ? did this start while you was working on it? if it did you need to back to where you just came from.

Those things are real spooks to figure out, and I sure don't have a definitive answer for you. I had a brand new '88 Chevy Dually once that started doing odd things, like the radio changing stations without my input, the heater changing blower speeds or temps, strange warning lights, and finally, the thing took to quitting running for no apparent reason. Got it towed into the dealer one afternoon, and a mechanic listened to my story, and started laughing; said I needed a replacement brake light switch, that there was a new service bulletin just out on it. With all of the electrics computer controlled, when one component in the system, such as the faulty brake light switch, starts to act up, it can affect any or all of the rest of the systems that are connected through the computer.

Good luck.

Originally posted by lt1s10
how did you keep that 4100 runing that long drg ?

Simple- im a mechanic and i dont take it to shops. As per questioning, No, it diddnt happen while I was fixing the TPS. Ironicly, it happened when i was picking up the tps from autozone! Anyway, i cant sell the thing. Its not mine. My mother went "Help!" and i couldnt leave her stranded. As for the foam coated board viking, they changed that. Now its all encased in a nice little box, er, boxes. More costly that way. But i have noticed a pattern. On countless chat boards for caddilacs, there is a constant referance to the "blower Controll Module" doesnt matter the year, make or model. If it has climate controll, these seem to keep going. Everything from a 88 brougham to an 03 sts. Through creative cross reference with my local advanced auto(IE: showing them how to run a parts book) I shall have that part tomorrow @ 11-ish. If it doesnt work(but i think it will) it will finally leave my #$%^ING Driveway!!! If it doesnt, the hunt begins. Thanks for the tips guys

Originally posted by DennyW
Your welcome.
Oh, I know your a mechanic, but make sure the power is unhooked when you plug it in.

Good point, and this is a bit of an update guys. Caddilac seems to have an issue with these climate controll modules. Now i know why. Upon pulling the module out of the heater core housing(?) I noticed that the cooling fins pointed straight downwards parallel to the heater core. Now if anyone here knows anything about electronics, it has never been a good idea to add heat to a computer. So, Naturally, They tend to barbeque. And as a side note, due to lowered resistance, they become sensitive to surges. Upon closer inspection, several transistors had burned. One clean off the board!:O So thanks for the tips guys, and keep an eye out for this one. Later