Instrument Cluster Overhaul

Summer 2006

My van is an 86, and came with the instrument cluster with the big clock and no tach. Even though it has an automatic transmission, I wanted a tach, which I find helpful in climbing and descending mountains, etc. My cluster was generally falling apart. The worst situation was the deterioration of the connection where the cluster connects to the wiring harness. The cluster has a printed circuit on the back which consists of copper traces in a flexible plastic sheet. The connection to the wiring harness simply leaves the copper exposed and the connector contacts these exposed conductors. Over the years the copper starts to corrode and sometimes peel off the plastic where the connector attaches. Last time when I took the cluster out, I had to repair one trace, and knew the end was near. Replacing my brake master cylinder this spring required removing the cluster, and caused more damage at the connection. Plastic fatigue had caused several of the screw holes used to mount the speedometer and tach to the cluster shell to break apart.

I had a cluster from an 85 van that I have wanted to install for some time. I had plugged it in before, and found that it had a problem with the coolant level warning light constantly flashing. And the 85 doesn't use the dynamic oil pressure warning system that the 86 does.

My goal of this overhaul was to repair the broken plastic parts of the cluster, combine the 85 and 86 clusters so that I had a tach, retained the dynamic oil pressure warning system, and had a coolant gauge that didn't flash at me constantly. I also wanted to permanently eliminate the problematic connector between the cluster and the van's wiring harness.

As of 9/1/06, I have had this modification in service for about 3 months and 2000 miles so far, and no trouble yet.