Tach help

[zaxxe30]

Hi so my tach, obc and interior lights were not working. Today I went out and bought some fuses and replaced fuse 21. After doing that everything worked. I plugged in just the yello and blue plugs behind the dash and left the white unplugged and went on a drive around the block. My tach was working just fine and my obc and everything. After I got back to my house I disconnected everything and took out the cluster again. I put it back in, everything else works now except for the tach but as soon as you turn the car off the needle moves up a little then comes back ddown like a check or something. This only happened after I took the steering wheel out and reconnected the cluster. could it be because I removed the steering wheel? please help asap

[zaxxe30]

wellll any help???

[Gregs///M]

Like I said in your previous thread, you are using an SI board that has 30 year old batteries. They are definitely near death which is why you are having intermittent failure.

You need to use a refurbished SI board before any additional troubleshooting.

SI board powers and controls tach, temp, MPG, and OBC. So any intermittent or complete failure of any of these gauges, and not necessarily at the same time, can be attributed to the SI board assuming fuse 10, 12, and 21 are new.