Diagnosing Cruise Control

[MotoScott07]

Hey, I'm new to the thread and just bought a 1998 GMC 1500 short box with the 4.3 and 4l60E. Everything checks out but the cruise control.. Nothing happens when trying to operate. Where should I even began to look to see whats the cause? Thanks!!

[RatPoweredTruck]

Fuses is a good start. Make sure it powers up. I think pinout goes like this....

A on/off from switch
B set/coast from switch
C resume/accelerate from switch
D normally hot 12v from brake/clutch switch
E ground
F hot in run 12v
G 0v/12v brake applied
H cruise inhibit pcm control
J cruise engage status to pcm
K vss from pcm/feed to cluster

[bperry]

do not want to steal the thread but I have a 1997 chevy C1500. Is there supposed to be a light that shows cruise engaged?

[imjeff]

If the brake switch fails the system won't light up. Easy to check and a somewhat common failure on the newer stuff.

Jeff

[Keith Seymore]

Originally Posted by RatPoweredTruck

Fuses is a good start. Make sure it powers up. I think pinout goes like this....

A on/off from switch
B set/coast from switch
C resume/accelerate from switch
D normally hot 12v from brake/clutch switch
E ground
F hot in run 12v
G 0v/12v brake applied
H cruise inhibit pcm control
J cruise engage status to pcm
K vss from pcm/feed to cluster

Look at the mechanical aspects, too.

Mine had the linkage pulled through the loop on the vacuum diaphram allowing the linkage to fall off.

I had to repair the attachment and re-install the linkage and then all was well.

Electrically - the wires coming out of the turn signal stalk and into the column are high failure areas, because operating the stalk fatigues them at a very specific (and repeatable) location.

Sometimes you get lucky and it's the easy stuff!

K