Hi guys, this is my first time posting.

For starters I have a 1981 RX7 GS with around 84,000km on the clock. I’m horrible with electrical stuff and this car is really testing me all of a sudden. With no prior issues, about two weeks back I pulled into a friends driveway and immediately after marking it over the hump by the curb, my tach, warning lights, and voltmeter go completely dead. The cluster fuse was intact. About 2 months prior I had pulled and replaced every cluster bulb with an LED direct replacement of which I’ve had zero issues with and was quite pleased with the improvement. Me and said friend immediately enter diag mode…we tested the coils, good… the igniters, good… the relay up by the booster, good. He gave me a USDM cluster to plug in and test and everything worked completely fine. So bad cluster? Fair enough…well the issues are persisting. I pulled my old cluster out and upon inspection noticed this blown connection seen in the attached photo.



so I attempted to solder it back together, went down to the garage, plugged in said repaired cluster and it blew the 10amp cluster fuse. Two more attempts and two more fuses later I assumed the cluster was fried and began looking at the replacement cluster my friend gave me. Since the replacement cluster was a USDM cluster with speed in MPH and generally in rougher shape, I went to the trouble of replacing every gauge from my Canadian Cluster, into the USDM housing with intact copper connections at the back (unlike my original housing). Upon attempting to reinstall and test my newly spliced together cluster, the 10amp cluster fuse blew AGAIN as well, I got a funky smell. Starting $&@%#ing bricks, pulled the cluster back and realized I was on the brink of blowing the exact same copper connection on the back of the cluster.

I already checked the ground for the cluster located up behind the dash and it was a-okay as well. So my question is…WTF IS GOING ON?! I’m beyond confused and I don’t know where to look next.

thanks in advance.

 

Something is shorted, probably in the cluster main board and this is why it blow out that foil run.

Check each side if that foil run to the ground point on the cluster board. This one is going to be a hard one to troubleshoot because it really needs to be plugged into the car, power off, to find a direct short.

It might be easier to find another Canadian cluster.

 

You're looking at a Ground circuit which is getting shorted to 12v, and I would expect it's something in the engine bay that's shorted; the printed circuit board is just the weak link. DO NOT replace the fuse with a higher wattage, or you risk a wire fire. You need to find the fault.

The reason why I say this is a Ground is that the trace on the printed circuit board goes straight to ground instead of through an Idiot Light Bulb. Note the bulb holders which get their signal from the pins on the board via connector, through the bulb, and then to ground - a shared circuit on the board.

If you can determine which signal is coming in through that connector, to the pin in question, that's the sensor which you need to look at under the hood. Check your FSM for the pin-out diagram and go from there.

 

Thanks for the prompt reply and assistance guys. Don’t worry I would never up the cluster fuse amperage in hopes to make something work haha. A friend of mine and knowledgeable Fb owner seems to think it’s my LEDs that are causing my problem. But they’ve been in there and al running fine for months until that day when my tach, voltmeter, and warning lights all **** the bed. Today I’m going to put my factory bulbs back in, replace the 10amp fuse and see if it blows again. My car is in fantastic shape so I’m quite lost on how this could just happen out of the blue.

If you care to see more about the car, I’m @thehakunamiata on Instagram.