2007 5.9 factory jake

[5050racing]

My vacuum pump is good jake works for a couple miles cold then no light or blinks sometimes then no jake at all no light on stick switch.I vacuum works the heater defrost vent moves so i should have vacuum. Any ideas haven't looked into much on this yet under the hood just figure i ask here thanks! I change the pump to my spare with new diaphragm just thinking it was pump but does the same thing as with old pump.

 

[AEdelheit]

Just an FYI the Vacuum pump for the Exh brake is completely independent of any HVAC controls .

 

[AH64ID]

Have you verified the switch is good?

Checked the ECM pins or wire splices underhood?

Just an FYI the Vacuum pump for the Exh brake is completely independent of any HVAC controls .

Yep, no vacuum for HVAC on an 07.

 

[Prairie Dog]

EB wasn't factory. It would have been added by the dealer.
Since the light isn't coming on, it has to be an electrical issue. As John suggested, check the switch and look for what ever wiring the dealer hack may have done. After that I would check the relay - when it fails just tap on it with something like a screwdriver handle. If it starts working, it's bad.

 

[5050racing]

Have you verified the switch is good?

Checked the ECM pins or wire splices underhood?




Yep, no vacuum for HVAC on an 07.

Ok thanks so i need to make sure i have vacuum,i bet the diaphragm i replaced the whole can not a kit but reused my old pulley part of pump may be ng,thanks for the help will post tomorrow what i find as i said i didnt do much after replacing the pump.Someone say about 25 in of vacuum is what im looking for ??

 

[5050racing]

Ok thanks so i need to make sure i have vacuum,i bet the diaphragm i replaced the whole can not a kit but reused my old pulley part of pump may be ng,thanks for the help will post tomorrow what i find as i said i didnt do much after replacing the pump.Someone say about 25 in of vacuum is what im looking for ?? Where is the relay located?

 

[5050racing]

Whats weird it works for a bit cold

 

[Prairie Dog]

Relay could be cooked or poor wiring connections can get grumpy.
Could be any of the things listed really.

 

[Ozymandias]

Download the install and troubleshoot manual, it will tell you exactly how to determine the fault.

The system is incredibly simple made.

 

[5050racing]

WOW you guys are unreal with the help here !!! Ozymandias thanks !!!!

 

[5050racing]

Still haven't had time but it works light on when cold then after a few miles like 10 and im in Florida so it not cold out stops working light goes out,where is the relay located at to save me time,looks to be by ac on passenger side firewall?

 

[mwilson]

Installation manual, Section 5 (Electrical) shows you the relay and placement.

https://www.jacobsvehiclesystems.com/parts-service-support#wizard

 

[5050racing]

So just got to look at this I have tested the switch have 12 volts on red wire switch open nothing on green n yellow with switched closed to activate jake only 10 volts on the green yellow wire would you say its the switch,I jumped the relay with a fused jumper jake works fine.Just not sure why low voltage to greenyellow or is that what flows on that going into ecm?I think just bad switch it was blinking then would stop lighting at all

 

[5050racing]

I couldnt pry apart the switch i think with out breaking it does anyone know if the switch is able to be split,i tested the wires below

 

[5050racing]

I just looked again at diagram i have 10 volts on yellow wire also so maybe its a ground issue in the system,i shouldn't have voltage on yellow wire at switch so its looking for a ground i think.

 

[Prairie Dog]

Be careful what you apply 12V to. If you send it to the ECM pin it may fry that particular driver in the comuter.

The ECM only sends a ground to turn on the relay.

 

[Ozymandias]

The switch is known to go bad, and it is a discontinued part.
There is a dash switch available as replacement.

 

[5050racing]

Thanks again I read installations I should get it from here no ideas on a replacement switch anybody?

 

[mwilson]

Thanks again I read installations I should get it from here no ideas on a replacement switch anybody?

Are you determined to keep it mounted on the shift lever?? Or would a dash switch work??

If you want to continue with a shifter mounted switch there is in my opinion only one easy clean non-gooberish alternative which is a switch for an Eaton two speed rear end...

I can give you some part numbers so you can search them out on Amazon or something if that is the route you want to take..

Will require the switch, wire harness and bracket..

 

[AH64ID]

My Jacobs switch was NOISY so I replaced it early in my EB's life with a switch from Pac Brake. It's shifter mounted and only uses 2 of the 4 wires as it doesn't have a light. It worked well for many years.