I'm about to kill this thing (gauges not working)
 

So.. 6 months of downtime and a lot of money's later.. My car is running with a rebuilt motor on MS and I'd love to drive it.

However, my gauge cluster gauges aren't working (don't know about speedo, but it's cable driven so I'm sure it does) The tach, op gauge, fuel gauge, and water temp gauge all have the same power and ground source, so I'm thinking that's gotta be it.

This is where it gets weird, I check ground at 2J on the connector on the back of the gauges, ground is good. I check power, no power, ok I think im getting somewhere.

Next I check the fuse, it's good, check power on both sides of the fuse (this is the meter fuse btw) power on both sides of the fuse. So I'm thinking it must be a cut wire or something..

I kill power, ohm out between 2K and the fuse, I have .3 ohm, WTF? I check for power again, and again I have it at the fuse and not at the connector.

So, I troubleshoot electrical systems on aircraft everyday at my job, and I'm feeling like an idiot, plus it's like 115 in my garage right now and I may be delerious (sp?) but can anyone think of what could be causing this besides my own stupidity?

Thanks

P.S. 1990 miata, haven't done any wiring in relation to the gauges

hmm did you build your own MS in parralel? i would suspect the MS before i suspected something i hadnt touched.

I haven't really looked at any schematic for the Miata.. but if you can ohm out the wire from the gauge to the fuse.. you should get power. So I don't see how you are not getting power unless there is something between the gauge and the fuse that is opening the circuit when there is power.

Have you tried running your own wire from the fuse to the gauges?

Any one have a e-copy of the wiring diagram for the gauges?

It's been a while since I've done any electrical diagnosis, but hopefully I don't sound like a retard and something I said helps.

You are right that I should have power, that's what's so confusing for me. I'm going to try to run my own wire tomorrow just to see if that fixes it. Here are the schematics: http://www.madracki.com/miata/images/wiring/90diag.pdf

Magna, I did build my own MS, however I dont think these gauges have anything to do really with the wiring that I touched over there, also it was doing this before I installed the MS (when I was running it off of the factory ECU)

check the power to ground, maybe it's grounding out

Not really sure what you mean, check power using the power pin for power and the ground pin suppied to the cluster for ground? that's what I've been doing if that's what you mean

check the resistance between power and ground at the cluster. You said you checked continuity in the wire, and voltage at the wire, but didn't say if you checked to make sure the wire wasn't grounded.

True, the wire coming from the meter fuse and going to 2k could be grounding out somewhere.

Had a similar problem with my '94. Solution to my issue is my build thread... https://www.miataturbo.net/forum/t34619/#post416876

That's true, but I assumed that it would pop the fuse almost instantly if it had grounded out.

H'mm im assuming these connectors you found on the passenger side were signal wires from the sensors, do they all run through the same connector?

I'm not sure if the 94 is the same as the 90 in that regard, I'll have to look, but I hadn't even though of that. thanks

You would think, but the only other explanation is that what you were testing against wasn't actually a ground.

I'm pretty sure it was but you never know.. I'm about to go out there with a level head and see if I can figure this thing out.

Seal that garage up tight and put an AC in there for god sake. 115F is way to hot to be working in. Then check the switched power on 1i and also the ground on 2d. Gauges look like simple anlog curcuits and could be verified with a direct connection the the gauge itself. hope this helps out.

Well those of you curious.. It was the power wire just like I and everyone else was saying.. Not exactly sure where it's messed up, but I ran a wire off the fuse to the gauges just to see if it fixed it, and it did..

So I removed the factory wire and more permanently put that new wire in, problem fixed now.. Thanks everyone

Just as I finished everything else up, got all ready to drive it, I realized two things.. One, my reverse lights don't work, Im thinking I possibly could have forgotten to hook up the wires when putting the engine and tranny in, but I dont think so, maybe wiring I hope not.

Second, what actually prevented me from taking it on it's maiden voyage :giggle: is that my radiator cap is MIA, so I gotta go pick up a new one tomorrow.

Ouch, that is a horrible thing to keep you from driving your car!

Glad to here the gauge cluster is up and running.

The wires for the reverse lights that go to the tranny were horrible for me when getting my car back together. I ended up just cutting the wires and putting in some easy to disconnect connectors.