I have 1992 Buick Roadmaster - the rpm stopped working. Is it a fuse..or what is it?

Question

what function is the rpm and will it harm my motor.

Answer 1

This vehicle uses a vehicle speed sensor to calculate the vehicle speed. This signal is then input into the pcm. the pcm does a calculation(4,000 pulses per mile)and tehn sends out a signal to the instrument cluster to control the tachometer,or the rpm readout. It could be the cluster itself, wiring from the vss to the pcm or from the pcm to the cluster. I had a roadmaster at the dealship where I worked that had a tachometer inop and it ended up being the multi function chime module, the black box that controls all the little warning chimes and such. Not sure if in 92 the roadmaster had an electronic trans or not. seems like it did. If it does, then if there was no speed signal from the vss to the pcm, the trans would not shift, and there should be a code 24 stored in the pcm for no vss signal. IF the trans is working ok, it's either a non-electronic controlled trans or the vss is working, just not getting to the pcm or the pcm is not controlling the cluster or the cluster is bad. IF everything else seems to work ok, and the rpm's not working doesn't bother you, just leave it be. It won't harm anything if the gauge doesn't work.

Answer 2

It's just a dial. It doesn't affect anything. It's job is to show you information.

If your motor is running, it has RPMs.

If you run your engine very hard, as in very fast (engine, not necessarily wheels), especially in a low gear, you can burn your engine out. The RPM dial (called a tachometer) is there (mainly) to tell you when you're working your engine too hard.

Lots of cars don't have an RPM dial at all (like mine); it's not a necessity.

Answer 3

chances are its a cable and unless you have a manual and you use the gage to shift i wouldn't worry about it