Hello all. Working on a 1988 244 m47.

I installed a volt gauge and started installing an oil pressure gauge. I ran power from fuse #4 for the volt gauge, and grounded it with the ground wire on the small clock. I turned everything on and it worked fine. I started running wire for the oil pressure gauge. To test it, I plugged the wires from the volt gauge into the oil pressure gauge and turned it on. The gauge shot to 5 bars and stayed there. I figured something wasn't working right, since I didn't have it plugged into the sensor yet. When I plugged the volt gauge back in, it only worked when the headlights were off. Now, when I turn the headlights on, I don't have lighting to my instrument cluster and the turn signal indicator lights stay on (not flickering). The volt gauge does not work when the headlights are on. Unplugging the volt gauge does not fix this issue.

Also, fuel gauge/temp gauge work fine regardless. Tachometer only works properly with headlights off. volt gauge and tach work a little bit if the headlights are on but the dimmer switch is turned all the way down. I have never had problems with this before installing the gauges, and idea what happened?

Thank you.

 

your overloading something...

I have a non rpm cluster on my 79 242 and installed a volvo rpm gauge from a 242 GT and worked great for a few days then blew up in my face....as if it was overloading....fuel works and temp...nothing else....I will need to replace...(my guess here)...instrument cluster stabilizer

that you can order for about 49 cents plus shipping...but you will have to solder...if that is the case...
k-jet.org has the description of the product and where to order....GOOGLE instrument cluster stabilizer...

I AM GUESSING I OVERLOADED MY CLUSTER THAT DID NOT COME WITH AN RPM GAUGE...

 

Thanks a ton for this. Documented my wiring but was losing my mind trying to figure out where the red/white connected too. No tach, so that explains it and I'm not going crazy.

 

Red/white wire is for a tachometer, if you have one. If you don't have a tachometer, it doesn't go to anything.

People tend to connect it to the double male spade on the back of the instrument cluster and end up frying a chip on the speedometer. Don't ask how I know.