I've had my 92 RS for about 2 months now and the tach doesn't work and it doesn't sound like most tach issues I can find. The needle stays pegged on 0 so I don't think the main issue is the tach board itself, I think it may be the physical tachometer, this is the only replacement I've found https://www.wc-autoparts.com/1990-92...v8-tachometer/. Whenever I have a chance I'm going to pull the gauge cluster out and test the resistors on the tach board, I can solder new ones in if I need to. I need to know if anyone else has had this problem and if there is any way to test the physical tachometer? I'm going to be replacing the whole cluster in a year or so when I put an lt1 in it so I don't want to spend too much on a fix for this. Thanks

 

I've got a fully working cluster in nice shape that tested all good when I swapped it in my car to test for a guy that needed one then, but that never happened. Originally from a 5.0 TBI if that will work for you. If interested get me your email address for pics and other info
Henry

 

Probably not the actual meter movement. The way those are made, there's not much to go bad.

I'd be looking for a loss of either power or signal to the circuit board.

See my signature for some intellectual help.

 

Okay, I think monday I'll pull it out and take a look. I looked a few minutes ago and it looks like the cluster comes out fairly easily, but how do I get the bezel past the **** for the lights? My car is missing the panel under the steering column so I dont have to worry about that.

 

You have to remove the **** or **** and shaft. If you reach under the light switch there is a kind of button sticking down you need to push up on to release the shaft which will just pull out. Later you just stick it back in...
Or you may just be able to pull the **** off, but be careful you don't lose the metal clip inside the **** that you will need to re-tension some when putting back together. First option is the best choice IMHO

 

Okay, I've got the tach out and just checked the tach board by following the sticky post, the resistances are as follows:
r1- 3.83k Lower than the others tested
r2- 3.81k
r3- 1.91k
r4- 302k
r5- 7.25k Much higher then the others tested
r6- 2.95k
So judging by that I would think that the tach should be reading something, not the correct rpm but it should at least be moving right? Does anyone have a pinout of the blue connector so I can test if its getting power when the cars running?
EDIT: I found a pinout of the connectors behind the gauge cluster and there is no signal coming from the coil to that point, There is signal coming out of the coil but there is a open somewhere in the wire. So I guess the only option from here is to try and find the open.