E30 Dash, HAVC , front ash tray lights are out - Help!

[Mike36]

Hey guys. Hopefully someone can guide me with this issue. So I started doing my dash swap on this weekend. I was able to remove it with out any issues, made sure to document what went were by taking photos with my phone. After a few issues with installing the crack free dash (FUN FACT: Not all dashes are created equal), I wanted to make sure all the dash bulbs were replaced before reinstalling everything. So I went ahead and bought new bulbs, replaced each one and tested them out by turning the ignition switch on. As I was reinstalling the lower parts of the dash. I noticed the lights (Dash, hvac) were flickering on and off. The battery shortly died after that (I had left the light on and key in the ignition when I left for a short break). Anyways, I took the battery to get recharged, When I came back and reinstalled the battery, I noticed the mentioned lights weren't working. I'm going to check all the fuses tonight and go from there. I did notice the headlight switch bulb still worked and but didnt dim when turning the headlight switch. Any advice would be greatly appreciated. This dash install has been kicking my butt for 3 days now...

And yes, I realize now the having the battery connected during the dash install was probably not the best idea but too late for that now.

[earthwormjim]

Sounds to me like you lost a ground. The dash and hvac lights all get their ground through the instrument cluster, which then goes through the headlight switch rheostat. Check the ground connections for your instrument cluster first.

[Mike36]

Sounds to me like you lost a ground. The dash and hvac lights all get their ground through the instrument cluster, which then goes through the headlight switch rheostat. Check the ground connections for your instrument cluster first.

Okay, I checked all the wiring and everything seems to check out. I was reading on how to bypass it the rheostat so I may do that next. If its the switch then that should solve the issue. If not, then I may have a bigger issue to tackle. I need this fixed by Saturday :(. What gauge jumper wire should I use?

[earthwormjim]

Okay, I check all the wiring and everything seems to check out. I was reading on how to bypass it the rheostat so I may do that next. If its the switch then that should solve the issue. If not, then I may have a bigger issue to tackle. I need this fixed by Saturday :(. What gauge jumper wire should I use?

There's hardly any current on that circuit, so don't worry about jumper wire gauge. A paper clip would even suffice.



If the jumper doesn't work at the light switch, then jumper the incoming and outgoing ground to your cluster for illumination. You might have a burned out trace on the cluster PCB.

[Mike36]

There's hardly any current on that circuit, so don't worry about jumper wire gauge. A paper clip would even suffice.



If the jumper doesn't work at the light switch, then jumper the incoming and outgoing ground to your cluster. You might have a burned out trace on the cluster PCB.

Where exactly would that be on the back of the cluster?

http://garagistic.com/uploads/images/e30%20vdo%20gear%20instruction%20pictures/e30%20vdo%20gear%20repair%20(1).JPG

[earthwormjim]

Where exactly would that be on the back of the cluster?

http://garagistic.com/uploads/images...pair%20(1).JPG

You're not going to see it on a picture like that, you need to look at the ETM.

http://www.armchair.mb.ca/~dave/BMW/e30/e30_89.pdf

I seem to recall that all the illumination low side wiring, the "ground" that meets up eventually at the light switch rheostat, was all brown/white. You can try shorting brown/white to brown (ground) behind the instrument cluster, to see if you start getting your lights back.


You lose the ability to dim lights if you start jumpering brown/white directly to brown though.

[Mike36]

Okay so the headlight switch seems to work fine and dims . What next?

[earthwormjim]

Do what I said earlier, bypass the illumination ground that goes through your cluster (brown/white), or open your cluster and see if you have traces burned out.

[Mike36]

Do what I said earlier, bypass the illumination ground that goes through your cluster (brown/white), or open your cluster and see if you have traces burned out.

I'll see if I can figure that out. The reason I don't think that's it is because the cluster was out the entire time. The bulbs were on and working without the cluster installed, then I did something which caused them to go out.

http://www.armchair.mb.ca/~dave/BMW/e30/e30co_92.pdf (page 71)

I was finally able to understand this better. So after reviewing everything much closer, it seems as if my cluster lights, hvac lights, front ashtray light is out. My rear ash tray and light switch light are working and dim with the headlight switch.

What exactly does the G200 do, i've seen it come up few times in my other searches.

[Mike36]

Diagram 1

[Mike36]

Diagram 2

[earthwormjim]

G200 is a ground point that screws into the bodywork behind the driver's side of the dash. It's behind all the big connectors and wiring, above the clutch pedal. As you can see in the ETM, it is where all illumination gets its ground after passing through the light switch.

I can't recall how easy it is to get to. You could try jumpering Pin 2 of the headlight switch to sheet metal or a bodywork bolt/screw, or any known good ground point, and see if you get lights.

I'm really confused, you said the switch dims some of your lights though, if G200 was bad, none of your interior lights would work.

Can you plainly spell out what your car does? What lights up and is dimmable, and what doesn't work?