Hi Everyone,

I added a large Tach to my 1989 240 DL along with an oil pressure and volt meter about 2 years ago. Everything worked fine until about 6 months ago. The tach has started to malfunction. Some days it works fine. Some days it doesn't move at all when I start the car. Most days it works for a bit, then drops to 1k, doesn't move for a bit, then slowly drops to 0. The tach won't move again until I restart the car, and sometimes it still doesn't move. Car runs fine.

Is there a way to test the tach? I'm going to have my dash apart to fix the odometer gear and upgrade my stereo. I'd like to test or replace the tach while the dash is apart.

Another quick question. Sometimes the Overdrive arrow glows dimly then goes out. Car is an automatic, and shifts fine. Glow started happening when it was cold, but is still happening now that its hotter. The intensity of the glow is different each time it happens. This doesn't seem to be connected to the tach problem, but I thought I'd mention it.

Thanks!

I don't have tattoos or a wiring schematic folded under my arm pits anywhere.

My best guess you have a loose or corroded connection on the "power in lead" to the instrument cluster. No to hard to pull it out. It may have been out for some other repair or modifications before you did your handy work! :-)

It could be as simple as one of the large plugs on the back. Might be being yanked by weight of the harness or miss routed wiring.

There are Volvo wiring diagrams on the net. They are less painful than tattoos I bet!
http://www.volvowiringdiagrams.com/?dir=

There might be things there.

Good luck scratching your head!
Phil