So I just bought this S12 with a KA24DE motor and tranny swap. It has a digital cluster and the speedo always cuts out. Some days it works, others it doesn't. Almost like there is a short in it somewhere. I read that the S13 uses a speedo sensor on the transmission vs a cable. Is it possible the sensor is going bad?
Probably or the cluster itself
I've been considering getting an s13 analog cluster and doing the swap. I really like the digital retro cluster but they always seem to have problems.
i thought the digi cluster didnt use a cable? will check after some trolling
Yeah check the cluster first because they are known to have issues after 20+ years lol
Just as an update to this thread. The Digi cluster is in fact cable driven. I also fixed the issue for the speedo. I still can't get the tacho to work though. I took the cluster out and first thing I noticed was a few connecting pins to one of the ribbon cables on the back were fried. I took some new solder to it threw it back on and bam. It's worked for 50+ miles now. LOL
^ Yeah, most people get afraid when electronic stuff crap out. But sometimes it's just a little fix like that and it work like new again!
It worked for 3 days with no issue but started acting up again today. 
Maybe gophers got to your wiring???
The wiring looks great. It's just the 30 year old circuit board on the digi speedo. I can't expect something that old and complex to work perfectly even 30years down the road. It seems fairly simple to wire in an S13 Analog cluster so I'll just go that route. I'd love to keep the digital for its pure awesomeness but it isn't worth not having a dash that works properly.
rednucleus on 03:51:54 PM / 06-May-13Maybe gophers got to your wiring???lol just my attempt at humor - Bill Murray and the gopher in Caddy Shack - that's why I'm a veterinarian, not a stand up comedian.
There ya go Dave- humor is fun, but not my specialty either.
I have the same issue with my speedo, hopefully not the cluster. Then when the speedo works, the odometer doesn't move. The digi odometer works when the speedo works. What bothers me is that the cruise drops off when the speedo quits, so hopefully that is just a flakey transducer, someday I'll swap that out and see.