No Cruise - Part II

[discoman]

Darn it! I just can't get to cruise to work.

Tonight I unplugged the wires from the vacuum pump, started the vehicle, turned the dash cruise switch on and used a test light on the wire plug ends. The test light did not light. My fuses are good. Is this a viable test for checking power to the pump?

What else could it be folks????

 

[joey]

This is all I can find.... I would apply temporary power to the pump to make sure all is well.

The vacuum pump is energised when the main cruise control switch is operated, and is actuated by the steering wheel and brake pedal switches. The pump provides a vacuum source to the cruise control actuator. A control valve in the pump provides for steady increase of road speed or purge of the system when the brake pedal is applied.

 

[discoman]

Hey joey,
ya, I bench tested the pump and it was working. How well was it working? I don't know, I have nothing to compare to. But it was pumping.
But it looks like I'm not getting power to the pump at all.
Could this be a problem with my steering wheel switches?
I have already tested the brake cutoff switch, and it too is working.

Help please anyone!!!!!!

 

[joey]

If the pump is not coming on with the dash swich, then it isn't getting power correctly. The dash switch (cruise on/off switch) should turn on the pump, also the brakes turn on the pump if I recall correctly.

If it does come on with the dash switch, then I would start replacing vacuum hoses. and the 'T' connector. (I replaced my 'T' connector with a brass fitting from walmart for fish tanks)

Check the dash switch to ensure output of power, not just the fact that the light is coming on.

 

[discoman]

The dash switch is brand new, as i destroyed the original in my primary investigation.
As for the vacuum lines, i took all three and hooked them one at a time up to the throttle diaphram and used my own lips to apply suction. I was able to actuate the diaphram and hold it in place with no leakage. So that tells me my lines and diaphram are good.
I'll look for the brass T-connector as a replacement, I don't trust the plastic. I'll probally replace the vacuum lines anyway with some fresh ones.

I thought i read a thread from some time ago that said something about the steering wheel clock spring. Could this be the culprit???

 

[joey]

Don't know about the wheel clock spring

 

[discoman]

Cruise is now working - Yippeee

Well folks, I finally got the cruise control working just a few minutes ago.

The problem was with the brake pedal and the switch located there. The pedal does not travel back far enough to fully engage the switch. When the switch is not engaged two things happen (in my uneducated opinion that is): 1 - an electrical circuit is broken and the cruise ECU thinks the brake pedal is being stepped on, thus cutting power to the vacuum pump; 2 - there is a simple valve in the switch that opens up and physically breaks the vacuum seal thus releasing the diaphram at the throttle linkage.
To "Fix" this problem....I taped a small nut to the brake pedal where it comes in contact with the end of the switch, thus depressing the switch further and allowing it to "engage". This keeps the vacuum in the lines and the pump now pumps.

A special thankyou to Joey for suggesting the brake pedal switch as a culprit. Also, thankyou to everyone else who gave some tips in my other thread.
Hey Joey, I did end up using fresh vacuum lines as well but I havn't been able to find a brass T-connector yet.

Anyways, thanks again everyone, I hope I can repay the favor some day.

 

[joey]

I am glad to hear you found the issue, most rover problems are little things, that can be a pain to find, but usually cheap to fix.

 

[camper]

Thank you for writing up the information in the forum. Sounds like the switch while extinguishing the brake lights (you did not see the brake lights on correct) has a second position that tells the ecu that the brakes are off.
Does the pump run continously if this circuit is correct. Also did the light for the crusie switch come on during this whole process before and after you replaced it? Should I hear the pump running when I turn on this switch if all is well. I don't think I understand why the pump runs if you do not engage the set switch on the steering wheel?

Thanks for any help and hope this will help others.

Camper

 

[98GRDisco]

So the problem was the brake light switch or is it called something else