Need help diagnosing gauge problems - no fuel, tach, si.....

Post Mon Apr 11, 2016 12:03 am

I could use some help. The other day I was intermittently loosing fuel, water temp, tach, mpg and si gauges. The "check" light was coming on and off. It was as if there was a loose connection and it was making a weak contact. The gauges started working less and less and now the simply have stopped working all together. I pulled the cluster out and do not see any obvious issue. I took the SI board out and measured the battery voltage and both batteries were 3.1-3.2v.

I am not sure what to check next. I wiggled all the wires and nothing made a difference. Can someone walk me through diagnosing this cluster? Thank you.

Post Mon Apr 11, 2016 12:30 am

solder connections have probably gone on the main board. you could try with a soldering iron and reflow all the connections?

or try another cluster

Post Mon Apr 11, 2016 3:58 am

I removed the gauges from the cluster, but did not take the gauges off of the board. Would I see this with just what I did or do I need to remove each individual gauge to see what is under there?

Post Mon Apr 11, 2016 10:27 am

I consider it highly unlikely that there is a problem with the soldering on the board. 'Dry' joints only occur as a result of bad design, and on the whole the E30 cluster design is excellent. There are just two places where 'dry' joints are likely to be found - each end of the large 220 ohm resistor, near the temp. gauge, on the main board and the pins for the plug for the speedo. on the speedo. daughter board.
My first checks, considering the range of faults you describe, would be to the ignition switched power supply to the cluster, which is mainly from fuse 10, on green/white wires, to pin 23 of the blue plug and pin 6 of the white plug.

Post Mon Apr 11, 2016 6:55 pm

Thanks Brian. So, it sounds like I should test for 12v on pin 23 and pin 6 when key is on? Sorry, electrical problem solving is not my favorite. Thank you for your help and clarification.

Post Thu Apr 14, 2016 8:58 am

I'd suggest investigating 'splice 319' in the nearside sill. A bunch of live wires converge here to power some of the things you have listed which failed.