instrument cluster warning lights

[Tom]

The main beam warning light was very dim, but changing the bulb solved that. If there is an issue in the cluster, could I take a feed from the closest indicator wire, and use that to power a warning bulb?

Not really. The main warning light positive rail is boxed in with diodes, so if you were to jumper something over to it, you'd like short out that logic and create problems. If the new bulb solved the problem, why do you want to borrow a feed? What's the problem you are trying to solve?

The new bulb solved the dim main beam warning light. I was talking about tapping into a indicator feed wire or maybe the hazard warning switch. and running the wire to a bulb separate from the cluster circuit. And using that for the indicator warning light.

I'd start by testing to see if B6 and b7 have continuity to the bulb socket pads. Conceptually, the cluster bulb is no different than a light bulb with two wires attached to it (b6 and b7 are the ends of those wires). If b6 or b7 is not connected to that bulb socket, you just need to find the break in the copper trace and patch it. Or if that seems intimidating, just tap into the B6 and B7 wires and run a jumper wire straight to the bulb socket. Hacky, but no worse than a separate bulb.

If the cluster is ok, then something is wrong with the wiring (or relay!) and you won't be able to find any easy indicator feed wire that will operate a bulb correctly. You could make a random light bulb blink in the cabin by just tapping into the exterior blinker bulb wires on one side, but you'd need to get creative to make them work on both sides without causing a short, and really creative to also make it work with the flashers too. Much easier just to hunt down the problem. As I type, I'm really wondering if the relay might be your issue -- that's what feeds the bulb. If the cluster tests good, I'd be inclined to borrow a spare relay and see if that fixes it.

[jeyjey]

My car had a poorly-repaired cluster when I bought it.

cluster1.jpg (1.29 MiB) Viewed 74 times

I bought a salvage cluster and swapped the circuit board over:

cluster2.jpg (1.53 MiB) Viewed 74 times

[blade7]

Not really. The main warning light positive rail is boxed in with diodes, so if you were to jumper something over to it, you'd like short out that logic and create problems. If the new bulb solved the problem, why do you want to borrow a feed? What's the problem you are trying to solve?

The new bulb solved the dim main beam warning light. I was talking about tapping into a indicator feed wire or maybe the hazard warning switch. and running the wire to a bulb separate from the cluster circuit. And using that for the indicator warning light.

I'd start by testing to see if B6 and b7 have continuity to the bulb socket pads. Conceptually, the cluster bulb is no different than a light bulb with two wires attached to it (b6 and b7 are the ends of those wires). If b6 or b7 is not connected to that bulb socket, you just need to find the break in the copper trace and patch it. Or if that seems intimidating, just tap into the B6 and B7 wires and run a jumper wire straight to the bulb socket. Hacky, but no worse than a separate bulb.

If the cluster is ok, then something is wrong with the wiring (or relay!) and you won't be able to find any easy indicator feed wire that will operate a bulb correctly. You could make a random light bulb blink in the cabin by just tapping into the exterior blinker bulb wires on one side, but you'd need to get creative to make them work on both sides without causing a short, and really creative to also make it work with the flashers too. Much easier just to hunt down the problem. As I type, I'm really wondering if the relay might be your issue -- that's what feeds the bulb. If the cluster tests good, I'd be inclined to borrow a spare relay and see if that fixes it.

Good point about tapping into the wires for b6 and b7, thanks for explaining that. Could the relay not be feeding the bulb if all the flashers are working?

[blade7]

My car had a poorly-repaired cluster when I bought it.

cluster1.jpg

I bought a salvage cluster and swapped the circuit board over:

cluster2.jpg

Was any soldering required to fit the new circuit board?

[Tom]

Good point about tapping into the wires for b6 and b7, thanks for explaining that. Could the relay not be feeding the bulb if all the flashers are working?

It looked to me like the relay had a dedicated cluster output, but I misread it. I went to test that theory I found a real surprise. The schematic shows the relay as a 4-pin device with one output I mistakenly took to be the output for the cluster light. When I went to the car to confirm that, I discovered the relay is actually a 3-pin device -- even though the socket is indeed a 4-pin socket. So going back and tracing all the connections, it turns out the schematic shows a separate interior 'trailer turn signal' output -- which was either an abandoned idea or an option I've never seen. So my comment was based on a funky schematic, but still worth trying a different relay if you have one. Does your hazard light switch work? That's another place where I could see the signal getting screwed up.

[blade7]

Yes the hazard light switch works. Think I'll try some fine wet and dry and contact cleaner on all the pins, not confident that will cure the fault though. It would probably be a last resort to connect to the wires for b6 and b7 in the loom, can you identify the colour codes for those wires?

[Tom]

Yes the hazard light switch works. Think I'll try some fine wet and dry and contact cleaner on all the pins, not confident that will cure the fault though. It would probably be a last resort to connect to the wires for b6 and b7 in the loom, can you identify the colour codes for those wires?

I can look them up and will post in a bit. Do you have a multimeter to test if those edge connector pins have continuity to the bulb socket. Need a little video showing how? That's really the very first thing to do...

[blade7]

I do have a multimeter, but I could definitely use a video showing what to set it to, and how to use it in this case. Same with a 12v source, car electrics aren't my strong point, but I could follow step by step instructions.

[jeyjey]

Was any soldering required to fit the new circuit board?

Nope. It's all little plastic poppers and screws.

[Tom]

Here's a video showing how to use a multimeter to test the indicator circuit on the cluster. I made it fairly generic for a wider youtube audience, but if you watch to the end I also show how to test the indicator light with just a 9 volt battery. If your cluster passes these tests (multimeter or 9 volt battery) with a regular light bulb, the the cluster isn't your issue.

p.s., if you don't have a 9 volt battery clip, you can just have a helper hold wires to the battery terminals for testing....