Community Forums

Safari137 · 07-11-2014, 08:07 PM

Hello,

I'm new to the forum...kind of anyway...I've used it for a couple years to find a lot of info, but I'm stumped on this one and can't find my answer.

Recently my cruise control and vent options (A/C, Floor, Defrost) all stopped working. I discovered that a switch that turns on the vacuum pump, which is located in the engine bay (I have a diesel pusher), was broken off and not working.

The I connected the two wires that were connected to the switch and can hear the vacuum pump running. I even tested the vent controls and they work now. I haven't driven it yet, but I assume the cruise control may even work too.

So my questions...

1) Does the vacuum pump need to turn on and off OR can I just leave them connected? The wire is only "hot" when the ignition is on.

2) This switch seems to run off of a vacuum as well. I cannot find the parts to replace this with and the part numbers have either worn off or they never had one to begin with. Any idea what I need to get? (I've attached pictures)

(first two photos)
This is the vacuum line and what the switch was connected to by some sort of plastic glue. You can see the two wires that I not have manually connected. I also seem to have a vacuum line missing?

(last photo)
This is the electronic switch made by some company called Omron. It was attached to the back side of the object in photos #1 and #2.

Thanks in advance.

AE Gary · 07-11-2014, 08:53 PM

If you leave the wires connected the vacuum pump it will run all of the time. The first photo is of a vacuum diaphragm, it is like a pressure switch in reverse. If you have no leaks in the vacuum system this switch will turn off the pump when max setting on the switch is achieved. You would only need one vacuum line running to the diaphragm. Go to a Napa store and show them what you have and they will be able to help you with a vacuum switch that will do the job.

Safari137 · 07-11-2014, 10:10 PM

Awesome, I can stop looking for the other vacuum line then!

I'll go by NAPA and let you know how it goes.

Thanks!

Skip426 · 07-11-2014, 11:18 PM

The switch in the last picture , an interrupt switch, I have installed them as , cut out for cruise control; on standard transmissions, to detect clutch pedal movement, as part of the install package. I'll try and track a part number.

AE Gary · 07-13-2014, 10:33 AM

Also try this, connect the two wires together to make the pump run. Disconnect the line to the pump and plug it. If the pump stops running then it is equipped with an internal shut of switch, which most of them are. If this is the case the other switch and diaphragm does something else in the circuit which will have to be determined. In the pictures I cannot see the relationship between the diaphragm and the switch. You can check to see if the switch is working by hooking a ohm meter to the two contacts and operate the little button on the opposite side which should make the switch work and if it is NO or NC.

Safari137 · 07-13-2014, 08:54 PM

I will give that a try. I did test the switch with an ohm meter and it is not working. The contacts are corroded and even after cleaning then it didn't work.