Strange issue here...

Just finished my MegaSquirt2 install, and finally drove the car tonight. For some reason my speedometer isnt working. I damn sure didn't touch the transmission, and I didn't pull the instrument panel.

Last time I worked on one, they were mechanical... connected directly between the tranny, and gauge. Is there any reason that the speedo wouldnt register a signal? Like a switch in the panel not being on?

I'm about to dig through the wiring diagrams, but if anyone has some insight, let me know.

Of course, this could just be coincidental... the cable could have broken... but I really wasn't playing with the drivers side at all...

 

FC3S Speedometer is purely mechanical. The plastic clip that holds it to the back of the cluster likes to become brittle with age, or the cable simply broke internally.

 

Looks like a G/R in X-21... IC to Front connector... I assume thats the same one I had to pull the Y/W for the coolant temp wire for.

 

Yeah, I figured this was the case... and the G/R wire may have no effect when I install it in the morning... I'll report back. If it doesn't work (and I'm pretty sure it wont), I'll pull the cluster. Its just hard for me to comprehend that this is a coincidence.

and my car is a bastard... S5 TII engine, S4 vert body, and a hack job of wiring - with the exception of my standalone harness, of course

 

2 places..the back of the cluster or the cable input at the transmission.if not attached Speedo no workie!

 

Before I started pulling back the carpet to add that wire, I read that it seemed to be used for a buch of stuff that I dont have anymore (cruise, etc). I pulled out the cluster, and the speedo cable was just sitting there unplugged.

Dont know how, or why (the clip was still intact) but I plugged it back in and am good to go!

 

The wire you're talking about is an output signal from the speedometer itself, the cable has to be spinning the speedometer head in order for that signal to be produced.

 

got it. thanks!

 

the cable runs through the engine bay and sometimes if you accidentally pull on it it will detach from the cluster.