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Working around BCM/electrical/? of a Saturn?

I posted earlier this year about a Saturn and whether it was worth keeping. That post is here:

My sister still retains the car but it’s really decision time. I’ve learned a bit more, and need to figure out what, if anything, can be done.

The car is a 2002 Saturn L200, 70k miles, great shape other than the following issues:

  • Needs a new battery and maybe a headlamp (easy)
  • Needs brakes of some sort
  • Has this weird electrical issue (main problem–see below).

The electrical problem is that when you turn the car on, the dash is out, and the rear red running lights are out. For this reason, it can’t be driven at night. Also, the fuel gauge is permanently on Full, whether it is full or not. So, the car isn’t a usable vehicle in this state, though our late mother drove it that way for a year or more. We thought maybe it was the BCM, but were recently told something else…

A BCM had been replaced previously with a used one, I think. The dealership’s old notes said they suspected the problem was actually in the aftermarket alarm/remote starter system. They suggested that if that were disconnected, maybe that would fix the issue. So recently I got to the car and removed it. The car still started, but the problem persisted (no red lights in back). I tried this in broad daylight, though, so not sure if I should have tried at night (will these lights and dash come on in the day?). I pulled the box of the aftermarket remote starter/alarm out, but did not do anything special with the wires that had been plugged into it. As I said, the car still started fine (though I did not try to drive it).

So, the questions are:

  • Did I “finish the job” in pulling the remote starter/alarm out? Or did I have to re-hook-up the wires somehow?
  • Would doing this in broad daylight prevent seeing whether this fixed it? (I don’t know if the dash and rear red lights should come on during the day)
  • If this hasn’t fixed anything, is there a way to bypass this issue and somehow just hook the dash and red lights in back up to electrical? Just sort of jerry-rig it to work regardless if the BCM or whatever is not working right?

To look at it is going to cost hundreds, and it may be foolish at this point without a better understanding of the possibilities, so that’s why I’m asking.

If my sister doesn’t buy it, I wonder if anyone would buy it at a discount who might be handier with this sort of thing.


Are you really considering selling this to you sister? This is bail out time. I don’t know what you mean by red lights at the back. The tail lights only are lit when head lights are on and the brake lights only work when brakes are use or emergency flashers.

My daughter has a 03 saturn, and that is one car with easy fixes, power steering pump, trans fluid and filter change, cooling fan etc. I think the car is worthwhile, but you need the right person to fix it. Hundreds in this car I consider minimal, My daughter wanted to buy a something or other because it needed brakes, I am like brakes are regular maintenance and would you sell your car if it ran fine? No way she says. So I ask why do you want to sell your car with a regular maintenance issue to buy somebody elses problem? That was 3 years ago and saturn has been good to her. She wanted a Jeep!

The fuel gauge stuck on full could be one of 2 things

Either the stepper motor at the back gauge is faulty. A mechanic can use his factory-level scan tool to sweep the gauges, and he’ll very quickly know if it’s the motor or not. A decade resistance box might also be handy, if it’s not the stepper motor. A skilled mechanic with some brains in his head could probably diagnose it with just the decade resistance box and no scan tool

Needs brakes . . . pretty self-explanatory. not really a reason in and of itself to get rid of a car

needs battery . . . again, no reason in and of itself to get rid of a car

as far as the dash goes, isn’t there a dimmer switch for the dashboard . . . ?

as far as those rear lights, are we talking taillights, brake lights, or what?

Have you made 100% sure all your fuses are good?

Have you verified that the rear lights are in fact NOT getting power?

Do you have at least a 12V testlight, or better yet, a multimeter?

A skilled mechanic could figure this all out in a reasonable amount of time.

as for that BCM, was it programmed after you installed it . . . it’s usually NOT just plug and play nowadays

Do not sell the car to your sister. GIVE it to her, if she really needs the car. No offense, but any 2000 Saturn isn’t worth much, and it’s not worth getting into a potential family squabble over what amounts to a few dollars worth

Correct me if I’m wrong, but I sense that you may not be mechanically- or electrically inclined, as far as this car goes

Someone w/basic auto-electric skills and a volt meter should be able to figure out why the tail lights aren’t working. They’ll just start at the light bulbs and sockets and work towards the battery, figuring out where the break in the circuit is happening First off is to check the grounding point for that circuit is good.

I think the first thing is to check if the taillights aren’t getting power

I suspect OP hasn’t yet done that, unless I hear otherwise