Vacuum Warning Switch?

[John Haggerty]

So what is the vacuum warning switch all about (the diaphram looking thing conneted to the vacuum header and has wire coming from it)? I've lost a vacuum belt before and recently lost the vacuum pump and never got any kind of warning.

 

[JPR]

Mine caused the brake light to come on. Of course that was when vacuum was low enough that there was no power brakes.

 

[Agnem]

That's what is supposed to happen, but most trucks will hold vacuum a while, so unless you loose the pump, and have to pump your brakes more than once, the light may not come on.

 

[John Haggerty]

So if I pull the hose off the header (and cap the header) I should get a brake warning light?

 

[sassyrel]

jump the two wires on the switch-should light--

 

[Agnem]

So if I pull the hose off the header (and cap the header) I should get a brake warning light?

Yes it should.