Dodge Diesel Question...

[KWentling]

Took a look at my '04 this morning. I have no such thing on my truck. Could it have something to do with 4 wheel ABS maybe? I've got the service manual on a CD that I could look at but my mouse roller is shot and that makes it pretty hard to navigate it. Maybe I'll get a new mouse this week yet. Sorry I'm no help, yet anyway.

Kim

 

[Dmace]

Took a look at my '04 this morning. I have no such thing on my truck.

Do you have cruise control? If you have an 04 diesel with cruise control then you have a vacuum pump. It wasn't until the switch to throttle-by-wire in 06 or 07 (I think) that they changed it.

 

[KWentling]

Do you have cruise control? If you have an 04 diesel with cruise control then you have a vacuum pump. It wasn't until the switch to throttle-by-wire in 06 or 07 (I think) that they changed it.

Truck does have cruise control.

Kim

 

[KWentling]

OK, I went back to the beginning of this thread and now see the pump is on the passenger side firewall.

The coolant recovery bottle on my 3/4 ton is on the drivers side right next to radiator and windshield washer bottle so I was looking on the bottle. Looking back on the passenger side firewall I see the air conditioner accumulator that is in his picture but there is no pump like that anywhere under the hood that I can see. My truck build date is 7/03. HO Cummins 6 speed manual quad cab short box. I guess the one tons are different under the hood?

Kim

 

[Willl]

It wasn't until the switch to throttle-by-wire in 06 or 07 (I think) that they changed it.

Throttle-by-wire was introduced in 98.5 when they went to the VP44 IP.

 

[Dmace]

My truck build date is 7/03. HO Cummins 6 speed manual quad cab short box. I guess the one tons are different under the hood?

Kim

Vacuum pump for the cruise control is for Automatic transmissions only.

Throttle-by-wire was introduced in 98.5 when they went to the VP44 IP.

Completely different system but technically still "throttle-by-wire". The newer system is completely ECU controlled.

 

[Willl]

The newer system is completely ECU controlled.

Quite sure the VP44 is also.

 

[KWentling]

Vacuum pump for the cruise control is for Automatic transmissions only.

Thats right. I looked in the service manual and discovered that. Couldn't find much mention of the pump except in the speed control section, but I did find in the electrical section that it is located where the OP's picture shows the pump in question. It is powered on with the ignition switch and is on the same fuse (#1, 7.5 amp) as the AC pump relay. Didn't see any external switching of the pump so it must be internal by demand. Looked around in the automatic transmission section but I didn't see any mention of vacuum in its operation. I have no idea where the vacuum lines would go other than the cruise servo, and possibly the transmission.

Kim

 

[Willl]

My 02, vacuum also is used in the HEVAC system.

 

[KWentling]

My 02, vacuum also is used in the HEVAC system.

In '03 they switched to electric servos.

Kim