Need 1 little thing from a late 90s shop manual...

[Pete M]

I'm trying (possibly in vain) to get a functional speedometer in my Jeep. I have an 88 Comanche with a 99 TJ tranny/t-case. I'm told that it's impossible to get the speedo cable to work with the electronic t-cases, so I got myself a 91 speedometer to wire in. Using my 91 shop manual, I've figured out what-needs-to-go-where with the speedo, but I'll be darned if I can figure out the plug on the t-case. There’s 3 prongs in there, so I imagine there should be 3 wires. Anybody have a late-90s factory shop manual that they can rummage around in to find out what the three little wires should go to? Ground/power/signal maybe? Thanks!
Jeep on!
--Pete

[Georgia Mike]

OK,here goes.......

There should be:
An orange wire=8 volt supply wire (from PCM) tied into the crankshaft position center and dash
A black/light blue wire=Ground
A white/orange wire=Vehicle speed sensor input to PCM

if you are looking directly into the female end of the plug,the wires should be in this order:

Upper left=White/orange
Middle upper=Black/light blue
Lower right=Orange


All this is from my '94 FSM and *should* be the same,as they are the same type FI as the TJ,but YMMV

Good luck with it :thumbup:

[Pete M]

Thanks! Now I guess I just need to get an 8 volt power source in my truck so I can try this out.
Jeep on!
--Pete

[Georgia Mike]

You do have the PCM don't you? It should be there in it's harness somewhere.

[Pete M]

The 89 manual shows a couple 5 volt supplies and a 7.1 volt sync supply (whatever that is). I haven't had a chance to look into a power supply yet, but shouldn't Radio Shack have something I could use? Anyone know what a "sync supply" is? Can I use 7.1 volts? Or do I absolutely, positively need to buy a late model ECM just for the speedometer?
Jeep on!
--Peter