73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: nucknoel89 on November 28, 2010, 11:01:31 am
-
Hi all, my 81 has been running great since the swap except for one thing...my speedometer doesn't work! I got the 91 Blazer cluster but I must have the speedometer wired wrong cause it doesn't do anything. From what I remember from wiring it up, it has 3 connections: a shared positive, a shared ground, and then the speed signal (which I believe is wire 18 on the plug.) The way I have it now, that speed signal is coming from the PCM (pin 50 on connector C2). Is this wrong? Has anyone else used a Blazer cluster with the electronic trans and what did you do to make it work?
-
Where's the DRAC?
-
Where's the DRAC?
What's a DRAC? Seeing as I don't know what it is maybe that's my problem lol
-
http://www.tbichips.com/drac/
-
http://www.tbichips.com/drac/
After looking at that it sounds like the DRAC is a unit that reads the signal from the speed sensor and then sends a signal to the speedo based on gear ratio and tire size. But I had that crap programmed into my PCM (03 5.3 Vortec) so I figured the computer did that kind of work. Or do I still need a DRAC?
-
So you are running a 5.3L PCM? What year is the PCM and harness from?
-
So you are running a 5.3L PCM? What year is the PCM and harness from?
The PCM and harness are from a 2003, and they are original to the engine. And when I had it reprogrammed the guy put in the correct gear ratio, tire size, etc. for me.