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electrical mystery

5980 Views 8 Replies 3 Participants Last post by  u359200
I have a 97 DeVille. I hope someone could help me figure the problem I am having with it. It acts as though I have a blown fuse. My interior lights, cigarette lighter, trunk light, glove box light, & mirror vanity lights do not work. Everyone one of these are on the same circuit - I have checked the fuse - it was NOT blown - but I still replaced with a known good fuse - nothing - I can't find anything wrong anywhere - Also, there is a confusing mystery to all of this. The lights that illuminate the twilight switch, power window buttons, passenger climate control knob, & the power seats stays on constantly no matter if the car is shut off or running.

Please help if you can.
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Welcome aboard,
I MAY have a little help for you. According to MY book those items are NOT on the same fuse. Are you looking at the engine compartment fuse panel? The interior lamps are on one fuse and the lighters are on another.
Yes, I was looking in the engine compartment & neither the interiors or the lighters work.
Yes, I was looking in the engine compartment & neither the interiors or the lighters work. Thanks
Well if you were looking at that fuse panel, you'd see that the systems you described are on a couple different fuses. If the fuses are both good, take a 12v test light and probe BOTH SIDES of the fuse to see if there is power at either side of the fuse. If there is no power on either side, you probably have a bad fusible link which supplies the power to the fuses or a broken (or disconnected) wire between the voltage source and the fuse. If you have power at the fuse (both sides), then you have a broken (or disconnected) wire directly AFTER the fuse(s).
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Looking at the fuse panel - the 2 top rows of fuses are dead - no power.
all other fuses have power
The headlights are also on the row of dead fuses, but the headlights work?????Huh????
I used the 12v test light on the headlight fuse also- no power
I turn on the headlights & the 12v test light & the headlights light up??????
- I checked what appears to me to be the MAIN wires feeding power to the top fuse block - there are 3 8-10ga wires that I figure would be the main power supply??- 2 Red wires & 1 Purple.The 2 reds have power. The purple is dead.
Any idea where to check first.
Where is the fuseable link?

Thanks for all of your help!
Now you're making sense. Check the "Inadvertent Power Relay' Maxi Fuse. It's located in the engine compartment left Maxi-Fuse panel and it's labeled "INADVERT". The Relay is also there and you can check it while you're there. This Maxi-fuse also feeds the A/C blower motor so if the blower motor is out, that's probably the reason. If the blower motor works then it's probably the inadverent power relay causing the problem. The reason you're not getting anything at the headlamp fuses is because they only have power when the headlamps are on.
I just logged on to tell you I have found the problem & read your latest reply.
You were right on the money!!!! The Inadvertent Power Relay has 1 terminal busted off it from corrosion.

Thanks A Million!
I have the same problem and I changed the relay and I am still having a problem any answers.????
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