Mine has done that at as well. It was working fine then up and quit on me and then sometimes it was intermittent. I noticed when it would quit while driving that my brake controller would be illuminated...so when it did it and would not work I would just slide my manual lever over on the controller and all was good. Then I dug a bit deeper into it, and had to replace my trailer wiring harness it was shitting and would kill the cruise.
Confused on Cruise Control issue
- Thread starter jmaz268
- Start date
Well the rear harness looks to have been changed to a drawtight one, so guess I better dig into that too..
Based off of Alldata it has one...guess I need to look at it. it shows it under the hood on the back of the firewall, by the hydro booster it seems. Maybe something different for the 3500?
NSBU cost 56 bucks shipped as opposed to the 150 bucks. And a brake switch is about 20 bucks...
Yeah have to be careful with ALLDATA stuff. That module is for a cable operated throttle body on a gas engine. With what you have done so far I would go with the brake switch. You can always try wiggling the brake pedal and hitting the cruise 'Set' button at the same time to try to kick it on but that has only worked once for me.
This is a theory but you can pull the fuses to the trailer wiring and theoretically that would eliminate the possibility of voltage being back fed into the body from shotty trailer wiring. However that's a theory, have never had to try it (always was a brake switch)
I'll grab one on the way and install it tonight, seems they are 12 bucks at oreilys
I have a utility trailer that will knock mine out, along with my right turn signal whenever I pull it at night and the lights kick on... One of gm's wonderful wiring mystery's, but thats the only time it happens I know it has something to do with the wiring harness on the trailer but still doesn't make sense why it specifically takes out those features
One of gm's wonderful wiring mystery's, but thats the only time it happens I know it has something to do with the wiring harness on the trailer but still doesn't make sense why it specifically takes out those features
The only trucks that have a "cruise control module" are the trucks that are NOT drive-by-wire.
All duramax's are drive-by-wire, all 8.1's are drive-by-wire, and all 2003+ small block V8 gassers are drive-by-wire. SOME 2002 and earlier small block V8's were drive-by-wire but it was rare. The 4.3 V6 didnt go drive-by-wire until 2008 I think.
Any truck that is drive-by-wire, cruise control is an integral function to the ECM itself.
But to answer your question...you really need a Tech 2 to further diagnose this easily.
You can also pull the ECM connector and check for +12volts at the "set" cruise control wire, which is a DARK BLUE wire going to pin position 19 on the ECM C3 connector. C3 is the bottom-most gray connector on the ECM. IE, the signal wire from the "SET" button on the turn signal stalk should go +12v when the SET button is pressed. Make sure the cruise control switch is "on", then have a helper press and hold the "SET" button (with the ignition on) while you check to see if you're getting +12v at the "cruise set wire" going to the ECM...
All duramax's are drive-by-wire, all 8.1's are drive-by-wire, and all 2003+ small block V8 gassers are drive-by-wire. SOME 2002 and earlier small block V8's were drive-by-wire but it was rare. The 4.3 V6 didnt go drive-by-wire until 2008 I think.
Any truck that is drive-by-wire, cruise control is an integral function to the ECM itself.
But to answer your question...you really need a Tech 2 to further diagnose this easily.
You can also pull the ECM connector and check for +12volts at the "set" cruise control wire, which is a DARK BLUE wire going to pin position 19 on the ECM C3 connector. C3 is the bottom-most gray connector on the ECM. IE, the signal wire from the "SET" button on the turn signal stalk should go +12v when the SET button is pressed. Make sure the cruise control switch is "on", then have a helper press and hold the "SET" button (with the ignition on) while you check to see if you're getting +12v at the "cruise set wire" going to the ECM...
Thanks Ben, my only question there is will it matter that I'm not going 25+mph to activate it?
My cruise hasnt worked on my lbz since i bought it with 66,xxx. Went to dealer to get injectors replaced under warranty so had them check out what was wrong with cruise. They concluded after 3 hours of diag. That the fuse box was bad and wanted 600 $ to replace it.
What about the cruise control on switch? Where does that wire go? Is there any way to test it to see if it is sending the proper signal to the ECM?
any other way besides tech 2?
I have a p0504
replaced brake switch
replaced multi function lever.
need to find a massage girl for my sore leg from over 100k in just over a year with no cruise
I have a p0504
replaced brake switch
replaced multi function lever.
need to find a massage girl for my sore leg from over 100k in just over a year with no cruise
I have replaced 2 different entire fuse panels under the hood on LMM's. One was a windsheild wiper problem and can't remember the other.
My cruise works but will kick OFF when I hit the ACCEL button to bump up the speed... usually only does this when it's cold out. Once the truck warms up, it accel's fine....usually....
Did a deep pan today, so figured what the hell switch out the NSBU......
No change. Was doing alot of maintenance, finally put on my AFE bladerunner, oil change, fuel filter change......deep pan with the goodies, and a brake controller...
ran out of time to check the ecm ports.
I was going to do an EGR blocker as well, until I found that it already had one. So I was wondering, if it was possible that it was tuned before.....and if it was....is it possible that a different OS was loaded that didn't have Cruise??
No change. Was doing alot of maintenance, finally put on my AFE bladerunner, oil change, fuel filter change......deep pan with the goodies, and a brake controller...
ran out of time to check the ecm ports.
I was going to do an EGR blocker as well, until I found that it already had one. So I was wondering, if it was possible that it was tuned before.....and if it was....is it possible that a different OS was loaded that didn't have Cruise??
No, all OS's have cruise (PTO) setup, regardless of whether or not the truck had "cruise" fromt he facotry