cliffjumper

I recently bought a 1991 S2 which seems to run well, but has very few warning lights during the system check. Turning the ignition to on only brings up the big !, the seatbelt, ANTILOCK, and the battery voltage warning lights. All of these extinguish when the car is started.

I have done a search on a few forums and found a couple of threads which never got solved. I've taken the gauges out, all bulbs are fine and the circuit board and connectors all seem intact. Does anyone have any pointers on what to check next?

cliffjumper

pictures of the dash during system check:

PaulD_944S2

With the mileage that high, you may need to pull the instrument panel and check to see if some of the indicator lights are burned out.

cliffjumper

Thanks Paul, I've taken out the dash and checked all bulbs using a 9V battery. All warning bulbs and normal dash lighting bulbs are working.

PaulD_944S2

Next try gently cleaning the ribbon cable terminals by rubbing a pencil eraser on the exposed copper terminals.

Since you have more than one indicator not working, you may have a bad connector elsewhere, or a bad ground connection.

Also, you may want to locate an electrical schematic and do some basic voltage checks. Pick one circuit like the parking brake and trace it out.

cliffjumper

Thanks again Paul. I've just tried cleaning the contacts on the ribbon cable terminals, as well as a few on the actual flexible PCB with contact cleaner, but had no luck.

I'll track down a schematic like you suggested. Is it going to harm anything if I reconnect the battery with the gauges out and check voltages at the ribbon connector terminals?

I found this connector unplugged while I was digging around the dash, can someone ID it? It was cable tied to the left hand ribbon connector. I guess there's a bunch of these style connectors under the dash, so sorry if this is a ridiculously dumb question! This is the most clear picture I could take with my phone. The part number is 944.612.550.000. I checked a few places online and found names such as "PLUG SOCKET". Not as descriptive as I'd hoped..

cliffjumper

I found the wiring diagrams for the 91 S2. I've traced out the handbrake and it looks like it's a separate issue to the other lights. I think the fuel reserve light is also ok, as it probably isn't designed to turn on during a system check and I haven't ever run low on fuel. As for the others, they all go through this "disconnecting point electric" on the schematic. A search for this didn't turn up anything, so can someone explain what this is? It's separate from the three gauge connectors, but is this actually some physical disconnection point?

cliffjumper

Putting all info I've found out in one place... I have managed to identify the disconnection points on the back of the dash cluster. They looks like solder points between different layers of the flexible PCB. If anyone in future needs this as a reference, here is a map of the bulbs and the disconnection bulbs as far as I can tell.





Testing connectivity across inputs and outputs (e.g. point 4 and point 6 for oil level warning) shows no connection. This either implies a broken connection or there is more behind-the-scenes wiring going on between inputs and outputs. I have managed to get the brake fluid, gas, temp, oil pressure, park brake lights to light up by applying a 9V battery to the appropriate pins on connectors A,B and C. I still can't get oil level or brake pad wear lights to turn on.