Happened to me last year, bad speedo. Speedo powers the tach and I think the odometer. There were only a handful of new left if I recall correctly. While it could be a grounding issue my money is that it failed just like mine. Pull it out and check for cold solder joints if you don't find anything obvious I would start sourcing a new speedo or cluster.

Despite what a few sites claim the FD cluster only has a few serviceable parts the rest are replacement. The service part aren't typically what fail. I sent mine off repair to save the odometer reading, they were unable to repair it.

 

Welcome to my world. Mine don't work either. The cause of mine?



Been calling around to see about getting it fixed. Some shop want a working one so they can get the values of the diodes, others are shooting from the hip and quoting me a very high price and others would not even touch it.

My solution? Just going to replace all of them with these. Kill 2 birds one stone since I want to go with the Spirit R cluster. This way I can have them the way I want them with more accurate gauges without the cluttered of having gauges all over the place.

http://www.speedhut.com/gauge_produc...uto=revolution

 

I thought about doing the spirit r cluster. I just wish they made the speedo in mph.

 

The power FC get those reading from other sources it's consistent with the problem. As for your AC I assume that you have checked that it has refrigerant, if out or too low it disables itself.

I seem to recall that there is an issue with the AC and the PFC, I think that one is well documented. I replaced all that too last year, must have got the parts from the same bin... Early 94 touring here.

If it it isn't a groud with the AC I would try and build a custom AC setup from a more populare vehicle. FD AC parts are extremely expensive and IMO only marginal performers at best on R134. While my AC works for about $2500 it's nearly useless at idle and barely cools at speed. Every part in the engine compartment was replaced. I was one of those deals were it started with just the compresor and ended with replace that too while you're in there it's another $200.

 

http://rx7boutique.com/Interior.html

 

I know of someone locally that will check that out for you, well in St. Pete anyway. PM me if you want the info.

The secret decoder, I can't tell from the pic. Looks like black black gold on my display...
http://www.ehow.com/facts_7256252_do..._s-value_.html

 

Actually you can have it read MPH. Which the faces from the US cluster with the Spirit R cluster. Not only it will read in MPH but you will have your actual mileage too.

 

I know but with the prices they go for, you would hope they would mock some up, for people like me who want to keep it MPH. Like do up 2 clusters with the 93-95 speedo in it, already assembled etc.

Idk, i think 800+ bucks, plus you still have to do the switch yourself is a bit much.

But i guess cant have everything. Those clusters are amazing though.

 

I see what you are saying. Reason why I'm replacing all mines with aftermarket units for about the same price.

 

check this thread out

https://www.rx7club.com/showthread.p...ht=cluster+fix

BTW those are zener diodes. If you replaced the same one as the one I have that are burnt out, what values are they?

 

My speedo went out, I replaced it with a new one. The car was completely rebuilt from the groundup, new motor etc. So I was fine with letting it say 0 miles. But I'm looking into finding a schematic for these things, don't know if mazda would be willing to supply it but I will investigate that route. Then I can fix my old one as well. If anyone else has some contacts let's see if we can get the proper documentation. This will only become a bigger issue in the future. Even if you have a new gauge determining the appropriate components is not always easy.

 

you speedo is also supposed to be solder to the circuit board on the four points.

 

Mine is solid. Did you change the diodes? What value did you get?