Hello everyone. I own a 2002 Saturn SL2 and I'm having problems with the dashboard lights turning on. The odometer works fine the turn signal lights on the dash work fine all interior lights also work. I have noticed that the dimmer switch doesn't work as with the fog lights will not turn on also . And I also noticed I have no tail lights or brake lights when brake pedal is pushed in. Turn signal lights work, reverse lights work as with the brake light in the back window works. Tested all fuses under the hood and the fuses inside the cars fuse box. All are fine, all rear light bulbs are also good. Could it be the dimmer switch ?

 

Yes, it could be the dimmer switch. Most of us set them and never move them again. It might just need a good cleaning. I'd recommend some CRC Electrical Contact Cleaner. As for the brake lights, I'd take a look at the brake light switch. It might need replacement. Does the third brake light work at all? I'm pretty sure it's on a separate circuit.

 

Yes the third brake light does work. I tested the plug where parking light bulb goes into for power and there is nome

 

Sounds like time to hit the schematics. Give me a day or so. I can't see how the brake lights would be affected by the dimmer switch, but stranger things have happened.

 

I agree with you, derf. I THINK he has two separate issues here. At least he has the third brake light or the police might not like his car!

 

Two different issues indeed.

Instrument cluster and dimmer equals one issue.

Lights to the back equals a second issue.

Dimmer and instrument cluster

Oh joy, the dimmer switch high and low leads go to the BCM. Neither are ground, the high one supplies voltage and there is a variable resistor when you turn the ****. Based on the total voltage across these two leads, the BCM sends out a certain current at a given voltage to light the rest of the instrument cluster lights.

There are two possibilities. One is that the dimmer itself has failed in which case none of the instrument cluster lights like the radio HVAC control head instrument panel cluster prindle lamp, the dimmer switch itself etc will light.

The other possibility, well there are two, is that the park lamp fuse, 10 amps, in the under hood junction box is blown or the circuit is discontinuous. All of what I just described gets its power through that one fuse. That seems to include the part of the BCM that controls the instrument panel lights. Seems weird but that's what the schematic says.

The other possibility is that your headlight switch on the left stalk is defective and not making contact when you turn it from off to park and to the headlight on setting? Do any of the lights behave as they should?

A lost ground from one of the terminals on the body control module to ground would also hose all of this If the ground at the splice pack is no longer grounded to the frame.

So possible Park fuse under hood junction box, dimmer switch, possible light switch on stalk, possible lost ground, possible BCM failure.



Passlock activating, parking brake lamps not lighting

Passlock activating when it shouldn't is usually either the pass lock sensor in the ignition switch or the BCM because pass lock is built into the BCM.
Since you can reset passlock, the key sensor and BCM seem to be able to communicate. Likewise, since you can get the car to run, the BCM can communicate with the ECM. Which leads us to where is the problem? 8.5 times out of 10, the BCM goes bad. Usually it is not just passlock, It is passlock along with a bunch of other strange stuff that suddenly stops working properly.

As fate would have it, the same parking fuse mentioned above is responsible for all of the exterior lighting including the tail lights.

It is not obvious from the schematic, but the brake switch is operating properly to light the third brake light but not to light the parking or brake lights. Since it makes contact and only one place after the brake fuse, based on the rest of the mess I'm about to describe, let's assume the brake switch itself is fine for now.

It is also grossly non-obvious from the schematic that the BCM has some input into the entire exterior lighting circuit front and back. Can't really tell what it is because it is not labeled. It is a brown wire. It seems at first glance to only control the rear but if you chase your way around the schematics it feeds the front as well as the park fuse.

So we have possible burned out park fuse, possible bad ignition switch pass lock sensor, bad BCM, bad light switch on stalk.

Pull the park fuse and test it not in the fuse box. Also, look at the condition of where the Park fuse plugs in. Is it corroded or does it look nice and clean?

A lot of the s cars ended up having issues with melted contacts and corrosion underneath the fuse box itself. Meaning where the fuse box comes off, there are contacts that should touch the bottom ends of the fuses but due to corrosion or melting, they don't. So you can test the fuse in the fuse box and it will test fine. After you pull the fuse, put the light switch to park and measure the DC voltage between each of the slots to chassis ground. One of them should be 12 volts DC, the other should be zero volts DC. If you're not getting 12 volts on either of those with the parking light switch turned on to park or headlights, then the problem may be underneath the fuse box.

This is a simple and easy way to start the troubleshooting. You cannot really check anything else until you have power to the circuit.

I know this is a lot of blabber, but I kind of have to talk my way through it as I'm reading the schematic or my understanding disappears in 2 minutes.

Feel free to ask any questions. Remember, no power, can't test rest of circuit so no point in buying dimmer switch if it is a fuse box issue. You'd end up putting it in and seeing no difference which tells you nothing.

Slow and steady we will get there

 

Sorry for the absence , unexpected emergency out of town. Played with the car alot more and this is what I've got (or don't have). Alright I have high and low beams, left and right turn signals front and back, reverse lights, both brake lights third brake light, day running lights interior light and map lights, stereo works heater works etc... What doesn't work is dash lights, I have an automatic and the light that illuminates the P N D etc.. does not work, dimmer switch - fog light switch, no parking lights or tail lights as well as no side marker lights.

 

Might I also add checked the wires going into my fog/dimmer switch combo and found only the pink one was hot with ignition on.

 

Going to have to talk this out

Brake light switch and brake fuse intact. Feeds straight to brake light filament in rear. Implies the single ground from tail lamp which is shared by parking filament, stop lamps and side marker lamps is intact. Implies. This seems true for both left and right tail light as well as left and right side marker lamps in the rear.

Reverse lights both work
Turn signal lamps work front and back.

Parking lights and side markers

The current path for the rear left side marker is through the park fuse in the underhood junction box through the left light stalk on the multifunction switch to the instrument panel junction box to the side marker bulb wiring. However, the current path splits right before the side marker lamp bulb and current is sent also to the tail light filament of the dual filament brake tail light bulb. The fact that you are turn signals and brake light filament work implies that ground is good.

Not going to bore you with the next part which is that the wiring then leads up to the front left, over to the front right, and back to the right rear.
If the ground I just mentioned is good, the left rear lights should all behave if the park lamp fuse and the light switch on the stalk are ok. Actually the rear right park lamp filament and side marker lamp should directly follow what I described for the left. Sorry about that.

The easiest explanation is the Park fuse. Or an issue underneath the fuse box under the hood.

Or the left stalk light switch on the column. But since the headlights come on in headlight position, the high beams function, If the parking lights don't come on when you have this in headlight position, it pretty much has to be the park fuse since we know the headlights work. The chance of the one contact inside that switch for the park position being fubar d is pretty low.
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Interior cluster lights and PRNDL light

These two bulb groups both share their own private instrument panel splice pack. The splice pack itself is then grounded.

Lose this ground and you lose only the IP cluster lights and the prindle lamp.

With the key on and the park or headlights on, check for voltage on the gray lead of the PRNDL lamp to chassis ground. With the dimmer switch all the way clockwise, Should be 12 V DC. If it is, It means power is coming from the BCM to light all of the different lights EG radio, HVAC, IP cluster, PRNDL lamp And you have lost the aforementioned IP splice pack ground.

If it is not a good healthy voltage, then there may be an issue in the IP fuse box the dimmer or with the BCM itself. The above test lets you differentiate between a lost ground and a failed discontinuous dimmer switch./bcm but we'll call it dimmer switch for now. Trying to help solve your problem and save you money

Please do the tests above and report back.

 

Progress?