I bought this '89 with issues right after New Years, and the snow has kept me from working on it until this past weekend. The past two days I've been going after some of the niggling issues. One has me stumped:

The speedo/odo has never operated, but ever so often, the needle will flip up upon starting. Yesterday I crawled underneath and checked the resistance on the impulse sender on the differential. It's right on Bentley's target resistance. So I checked continuity through each of the wires from the impulse sender up to the harness clip onto the speedo. The wires are fine. I cleaned the contacts and reattached the harness connections to the speedo and drove it around the block and the speedo and odo worked just fine. I then pulled the cluster back out, took it to the workbench, and attacked the temp. compensation board. Put everything back together and called it a day.

This morning, the speedo/odo didn't work. (But the temp. gauge works fine now!)
I recalled that yesterday during the test drive, when the speedo/odo were operating, I had the cluster just sitting on the 'shelf' above the steering column whereas this morning, the speedo was inserted back into the dash. So...trying to reproduce the situation, I pulled the cluster loose again, and the speedo/odo came back to life intermittently. Strangely, when the speedo/odo were functioning, the 'Service' light would come on. Then the Service light would extinguish and the speedo/odo would stop functioning. Like the dummy that I am, I just can't remember if the service light was on continuously while the speedo/odo were operating during yesterday's test drive. I do recall it being on, but can't recall if it was on all the time. But today, I'm certain that they were both operating together but intermittently.

So...do I have a short or an intermittent contact in the cluster? Perhaps a cracked circuit board? Why would both the service light and the speedo/odo operate simultaneously and go out simultaneously? That's what's got me puzzled.

And, just to betray my ignorance of the LH 2.4 system, does the service light light because there's a code waiting for me to be read up under the dash, or might the service light be lighting because I nudged that black lever sticking out the back of the speedo cluster? I'm guessing that that lever is a reset lever which functions like the old O2 sensor button on the old cable-driven speedo's auxiliary service odo, but I could be all wet on that.

As always, wisdom from the 240 wizards is appreciated.

Rob Kuhlman