I'm finally getting around to fixing my cruise control. I'd like to verify my cruise control pump by attempting to trigger it while the vehicle is off. I pulled this diagram from the RAVE, but I'm not exactly sure how I should wire some jumpers.


My thought would be to connect the blue terminal to positive battery terminal and touch the black/red to ground to trigger the vacuum pump? And then touch the green wire to ground to trigger the dump valve? Of course by the wires, I mean the terminals on the pump which had the wires connected to them.

 

Robert

I have a TD5 so not the same CC but be careful you don't blow up the engine management ECU in your endeavours, it's expensive.

 

No I was going to note which wires went to which terminal on the pump itself. Then disconnect the harness from the pump and connect jumpers from the pump to the battery.

The worst I could do is blow up a leaking pump. Best case I could verify it's creating and holding vacuum.

 

Hey Robert! Any luck with this? I was going to try the same thing with my CC pump.

 

Yes this should work, make sure to unplug the pump from the harness and test on the pump itself. You should only need pin 4 and pin 5 on the pump itself.

 

check your 3rd break light before anything... I spent a long time trying to figure why my cruise wouldn't work... If the bulb is loose or burnt out it disables your cruise control....

 

I’ve heard this before, but based on my real world experience with my latest D2, it’s not true. The 3rd brake light was out in my ‘04 at the time of purchase and on the fly and drive of over 1k miles, the cruise worked the whole way with zero issues.

I think the OP has the right ideas, though. When I’ve fixed other systems, it has been either:
- The vacuum plenum
- The other vacuum lines
- The pump itself
- The clock spring behind the steering wheel
- The brake switch

Diagnosis is fairly straightforward working your way from the switch on the cluster, to the computer, to the clock spring (and steering wheel controls), to the stuff under the hood. From my research in the past, it seems to mostly be either the clock spring or the stuff under the hood.

 

At least for me on my '03 if it's out then it disables cruise. I can take it out and drive it and cruise wont work every time. Its worth a shot as for me its a fix and hopefully can help someone else