Several Electrical Failures in My Buick LeSabre 2002

electrical-wiring
fuses

#1

Buick LeSabre 2002

Several months ago, several electric items in my car failed… all at once. For the cig lighter especially, I looked through both fuseboxes (front and back) for any fuse that looked like it might be responsible for that circuit. I was checking the abbreviations on the fusebox diagrams and wasn’t able to find a busted fuse.

However, with several things going wrong at once, I wonder if it was some other kind of fuse or relay. I don’t have the equipment to check relays, thought I found how to do it on YouTube.

I was hoping someone had some experience with this and be able to tell me what might be causing them all to stop working at once.

  • Cigarette Lighter
  • Interior/Cabin Lights
  • Reverse Lights
  • Power door locks
  • Trunk light

#2

Get a multimeter, about $10-20, or borrow one. Measure the voltage across each fuse, it should be zero. If you read 12 volts, than that fuse is blown.

Or a $8 automotive test light. Should not light up when placed across a fuse.


#3

There’s a bulletin for certain Buicks of that era about a defective cigarette lighter which can short out and blow a fuse. Ask a dealership if it applies to your car. I"d focus on the cigarette lighter problem as there’s a good chance fixing it will solve some of the other problems.

You can’t always see a fuse is blown just by looking at it.

There’s both a relay and a fuse for the cigarette lighter. The fuse is number 65, 40 amps, in the rear fuse block, the relay is number 58, again in the rear fuse block. If I had this problem, first thing I’d do is remove fuse 65, look at it carefully under a magnifying glass checking for cracks, and use an ohm meter to bench test it to see if it is good or not.


#4

My advice would be to use a testlight to check for blown fuses

It’s cheaper, easier and quicker to use, versus the dmm

sears has a decent 12V test light which lights up red. Easy to see, if your head is stuck under the dash, poking at fuses


#5

“Get a multimeter, about $10-20, or borrow one. Measure the voltage across each fuse, it should be zero. If you read 12 volts, than that fuse is blown.”

That is true, but if you read 0 volts, it does not mean the fuse is good. If the fuse is blown and everything on that circuit is off, then you will not read 12 volts. It is better to put the black lead to ground and then check both sides of the fuse with the red lead. If you read 12 volts on one side and 12 volts or some voltage on the other side, the fuse is good, if your read 12 volts on one side and 0 volts on the other, then it is blown.


#6

Fuse checks, corrosion checks and battery terminal cleanliness and tightness checks aside… I BELIEVE you will see a secondary wire coming out of your primary fuse block under the hood… Make sure that connection is clean and tight. That connection feeds the in cabin fuse block.

Remove the cover of the fuse block under the hood…and look for a large HOT wire bolted onto the under hood fuse panel…this is the wire I mean. If the in cabin fuse block feed is wonky…you will see all sorts of craziness with nary a blown fuse. Real stuff…

Blackbird


#7

Things like the cabin lights and power door locks are tied to constant power which most likely is provided from the power panel under the hood. The circuits don’t require the use of a relay since they don’t require much current to operate them, so you don’t need to check any relays out. You should at least purchase a test light probe so you can verify where power is getting to. It is very simple to use.


#8

Apparently it’s under the rear seat.


#9

Thanks guys for your great suggestions. Before I could buy a multimeter, I ended up getting a donation to have a mechanic check it out, and it turns out it was the rear body control module. I’m sure it would have been a learning experience, but nothing would have come from checking more fuses and relays, it turns out.

It was pricey. But my Dad trusts the guys that did it. Has been using them for years.

They replaced that unit and all that had broken was back to working. I figured that it was something central like that, since so many functions died at once.


#10

Glad it worked out for you and thanks for the update. It’s interesting that they even have to control the cigarette lighter using a control module. The driver is next.