Front Wheel Drive Vacuum Solenoid

[jeepboy_90]

My 1975 C303 is not releasing the front wheel drive. I believe it is a bad vacuum solenoid behind the front passenger seat. A few questions.

 

1) Should it make noise when operating? 

2) Mine only has two wires #44 and JORD, is this correct?

3) Replace part #?

 

Any advice would deb great. I have vacuum to the one side of the solenoid, but no activation of the solenoid when depressing and releasing the dash switch.

 

Thank you

[Fredrik L]

Hi!

 

1 Yes

2 Yes

 

The most common fault is bad earth.

Conect the JORD wire to a known eart source an give it a try.

 

It´s very rare that the solenoid is broken

[Beau]

The solenoid says "click" when you turn on the ignition key. When you turn off the ignition key there is a sound off air being released "pchoff".

It is correct with two wires one is + and the other is - or JORD = Earth.

 

My guess is that your - wire is bad. You have no - (earth).

 

Check your Earth Cable and let us know.

[jeepboy_90]

Fredrick and Beau, thank you for the advice. I hooked up to a solid ground (earth) and it worked. 

 

Can I ground the unit to the frame and not use the JORD wire? Does this JORD wire feed any other items? Hard to follow on the wiring diagram. 

 

Thanks again

[Beau]

 Yes you can ground it to the frame or any convenient Point with Earth. Then you draw this earthwire with a switch mounted so you can reach the switch from the drivers seat.

The wire in question does not feed anything else.

[Beau]

The problem with no earth comes most likely from a pressure connector  with four lugs for four wires.

This connector is situated under the large lid on the floor above the gearboxes.

Picture 2 and 3.

In the drawing  it is no. 71.

Another possible cause is a pressure switch under the dashboard to the right of the brakecylinder.

In the drawing it is number 63

This switch is operated by the brake pedal. This switch is not 100% neccesary. You can put a wire between the two lugs and keep it closed permanently. The idea with it is that it gives you 4 x 4 drive when you hit the brakepedal hard.

Your problem is common.

[Halfsafe]

To supplement Beau's excellent description here is the schematic from the Australian C3 Master Manual. Note that it differs in not having the brake pedal switch.

[Beau]

 One more picture of the connector above mounted.

[jeepboy_90]

Thanks for such a detailed response. I'll give that a look later this week when I have time.

[jeepboy_90]

Had a little time today. Crawled under the rig and found the 4 way connector. It was missing one of the JORD wires. Tracked it down, connected and everything is working as it should. Thank you very much, I am sure I will have more questions.