I'm having some real problems troubleshooting my jumpy gauges. The fuel, temp, pressure and sometimes tach jump any time a load that affects something with the cluster is applied - turn signals, hi and low beams, park lights and hazards. The amount of deflection seems proportional to the load.
Here's a video I uploaded to YouTube documenting what's happening.
Cluster Troubleshooting - YouTube
In searching the forums, this appears to not be all that uncommon and the solutions all seem to involve grounds. The solutions others have found that I've tried include -
So I'm about out of ideas. Have I missed anything?
Some additional information about the car. It is a 1985 380SL. I got the car with a blown engine, so I have no idea what may have worked and what might not have worked before I got it. I've replaced the engine with an OM617 and the only thing that affected the cluster was I replaced the SL tach module with a 300D tach module (signal/ground and 3 screws) BTW no difference in the symptoms with the tach disconnected... or speedometer, for that matter. Temp sender, pressure sender and fuel sender are all original SL components.
When running, fuel, temp and pressure all indicate proper/expected values except when lights, turn signals or flashers are enabled.
Here's a video I uploaded to YouTube documenting what's happening.
Cluster Troubleshooting - YouTube
In searching the forums, this appears to not be all that uncommon and the solutions all seem to involve grounds. The solutions others have found that I've tried include -
- Add a ground to the cluster - made no discernible difference
- Check the engine-chassis ground - looks good and for testing I added a jumper cable between the engine and chassis. No discernible difference
- Replace burned out bulbs - all bulbs check good
- Clean grounds on cluster - done, with no discernible difference
- Look for shorts on PCB - board looks really clean - touched up ground solder joints just to make sure
- Check fuses - all fuses check good
So I'm about out of ideas. Have I missed anything?
Some additional information about the car. It is a 1985 380SL. I got the car with a blown engine, so I have no idea what may have worked and what might not have worked before I got it. I've replaced the engine with an OM617 and the only thing that affected the cluster was I replaced the SL tach module with a 300D tach module (signal/ground and 3 screws) BTW no difference in the symptoms with the tach disconnected... or speedometer, for that matter. Temp sender, pressure sender and fuel sender are all original SL components.
When running, fuel, temp and pressure all indicate proper/expected values except when lights, turn signals or flashers are enabled.
