Hi everyone. Thanks in advance for your suggestions.

97 Discovery 1 Cruise control light comes on when the switch is pushed. But it does not work. Really have no clues where to start. I'm pretty good mechanically just not familiar with the cruise control system and it's usual problems.

I bought this used and it has never worked since I have had it. Just decided it would be really nice to have it.

Any advice?

 

Just fixed mine. Got to know the system very well. ETM in RAVE may be your best friend trying to fix yours. This is what I'd do:

Unplug vacuum line from vacuum pump/solenoid. Suck on line. If CC actuator does not move and stay then you have a vacuum leak. Check the lines and brake switch valve. The switch is just above the brake pedal and sometimes falls out of its bracket.

Test the pump/solenoid. It only has 3 pins: ground, pump, and actuator. Check ETM for exact pinout and hook up to battery. Pump should create vacuum quick, and solenoid should click and hold vacuum.

If those work then you're left with a relay, diode, some switches, and a bunch of wires. What I'd do is remove the glove compartment tray to get access to the CC ECU connector. Each pin's purpose is listed in the ETM so use it to make sure the ECU is receiving the correct inputs. For example, if the speed signal terminal is not present then you know where to narrow down the search. Similarly, if it does not have ground, steering wheel switch, or dash CC button intput, then you also know where to look.

If all the inputs are correct, but the outputs are not, then it must be the ECU. I went through two bad used ECUs before finding one that worked.

Common electrical failures are the CC relay, wheel switches, dash button, brake switch ECU, diode, and speed signal.

 

You absolutely rock! This is exactly what I wanted. Thank you so very much. I'm traveling and will be on show site until Friday night. So this week end I will dive into it and let you know what I find out. Thanks again. I love my discovery. I have that huge ARB bumper on the front. Just the thing to make people get out of your way on those long drives into DC.
lol

 

any luck?

 

Not yet. The first check I did was the vacuum line. Found it had deteriorated. And I couldn't tell which port it went on because the other hose on the solenoid was missing. So I found one in the wrecking yard finally last weekend that I could look at and even got the solenoid just in case.

So I haven't had a chance to go further. Sorry for the delay. Got busy and stayed that way. I'll try and do a better job keeping you guys posted.

Thanks
John

 

I believe one port on the pump doesn't have a hose that goes on it though.. Am I right? Then again mine has one free port and yet my cruise control doesn't work... hmmm....

 

The one I got from the wrecking yard has a hose from the bottom of the unit that connects to one port on the opposite side. I'll post a picture on Sunday. I would do it now but my son is out with it and I have to work the next two days. If I can earlier, I will.

 

The vacuum line connects to the black fitting next to the white one.