I feel like this should be easy.

I put my car back together and the tach, coolant temp, and oil pressure gauges don't work. Maybe fuel too but dunno.

Here is what I do know:

1. They all use Ground H. Other things that use Ground H still work. I checked what I believe to be Ground H and it looks good.

2. I have two gauge sets, both have the same issues. It's definitely not the gauges. Or just really bad timing.

3. Some things that use Ground H don't work also, such as the interior lights, but I'm not certain that they worked before. First time trying to turn them on.

4. Turn signal lights, brake light etc.. all work on the gauge cluster.

5. Turning the key on with the engine off the tach will move a bit to line itself up with 0.

6. Car runs fine and MS gets a tach signal.

7. I traced the Ground H and couldn't find any connectors that were unplugged, but I may have missed something.



My next test is to ensure Ground H at the cluster is in fact getting a good ground. If it is then I'm extremely confused and upset both my gauge clusters stopped working at the same time.

If Ground H is not getting continuity at the cluster then something odd is going on. Unless I missed a connector (there are a few unused but as far as I know they are all attached).

Am I going about this wrong? Is there another place (engine bay?) where all these things are related?

 

I had this issue and it was an unplugged connector. Under the blower motor if memory serves. This strange sort of issue is typically something pretty dumb that just got overlooked.

 

Interesting. Well I have removed all HVAC stuff so I might just have to improvise. I was thinking about just cutting the ground at the cluster and running a new one.

From the wiring diagram it doesn't really show how the cluster actually gets to the Ground H point, like if there are any connectors that must be used beyond the one that connects to the cluster.

The car drives fantastic. Just no tach is super annoying.

 

Which wiring diagram are you using? The factory service manual wiring diagram shows connectors. There's a sticky that has it. That's the wiring diagram I would use.

 

so, basically your tach doesn't work?

 

My tach doesn't work, my coolant temp doesn't work and my oil pressure doesn't work. Judging by the shared groundI am assuming my fuel gauge doesn't work either, but it's at 1/2.

Today I'll check to see if the cluster is getting a good ground. I traced the ground from the cluster to Ground H and there are no connectors, a straight shot. Unless something funky happened behind some of the wire wrap I'm at a loss. But other things that use Ground H still work. So somewhere along the lines things go down hill.

The only other thing I could think of is if all those gauges share a connector in the engine bay (igniter/coolant temp sensor/oil pressure), and that is disconnected, but that seems highly unlikely.

 

i dont think it's a ground issue; think other side.

How about this, what DOES work on the cluster? sure your meter fuse isn't blown?

 

Meter fuse is good, checked it. Everything BUT but the coolant/oil/tach/(fuel?). The turn signals work, the little light that goes on when the headlights retract turns on, the e-brake light turns on..

The fact that the gauges center themselves with key on leads me to believe none of the gauges are getting a signal. So maybe there is a connector in the bay or near the firewall I missed that hose those all bundled together.

 

do the CEL, ABS, AIRBAG, lights come on? I'm assuming yes cause you said ebrake does.

 

Those don't, but they also don't have bulbs.

I just found this: https://www.miataturbo.net/general-m...nt-work-72484/

So maybe I am just a retarded and didn't connect something.

 

Yep I did the exact same thing. WTF. I looked at this connector 100000 times and I thought they were two male ends. They don't *seem* like they should go together. But they definitely do.

I shouldn't touch cars.

 

lol. so you just forgot to plug one of the connectors in?

 

Yes. I also thought they were from the HVAC stuff. I also am retarded.

But it makes me feel better knowing that was my only mistake after basically redoing all the wiring and moving a bunch of ****. I had to reverse engineer so much aftermarket wiring.

 

I have a similar issue. I dropped my motor back in and the gauges mostly work, but at higher load, high speed, and letting off gas at high rpm, the tach, coolant, and oil gauges go all ***** nilly and won't stay steady. Idk if it's a ground a missed (where is ground H?) or could it be something else? Everything looks good on tunerstudio

 

Maybe the connector is loose, or could be the Ground. From what I gather ground H is on the FAAAAR passenger side, near where the passenger right foot would be.

 

Thanks!