Electric Speedo

[mags468]

I have a 1990 Suburban R1500, can the electric speedometer be switched to mech.?

 

[Vbb199]

Pretty sure that's possible, but you'll need a tailshaft housing and the correct drive/driven gears from a 89 and down.

Only thing I'm not so sure of, the ECM needs that signal in order to achieve lockup on the transmission and for cruise control to function.

But to the best of my knowledge, it's obtained 1 of 2 ways, (cable or wired)

Wired (like yours) :
on my 90 I had, it had the vss at the trans, which next went into the back of the speedometer, then you have the DRAC module (approx under your radio, behind the dash). Which defines tire size and gear ratio to properly calibrates the speedometer's electric signal (pulses) going to the ECM.

Cable:
Like my 89 or 87, you just have the cable of the tail housing leading into the speedo, and the vss behind the speedometer has an optical sensor of some sort that reads off of the speedometers rotations to communicate (via pulses again) with the ECM for lockup.

 

[Vbb199]

Someone may have better input on this subject, with a more descriptive explanation, but that's to the best of my knowledge how the 2 setups function.

 

[mags468]

Thanks for your help.

 

[Vbb199]

Thanks for your help.

What's your motives for switching over? Is your speedo getting stuck at 63 mph like they all seem to like to do?

 

[Billy]

I have a 1990 Suburban R1500, can the electric speedometer be switched to mech.?

I have a 1990 Suburban R1500, can the electric speedometer be switched to mech.?

I will gladly swap you my mechanical setup for your electronic setup