Cruse Control

[CJustice]

I do not have cruse control on my 99 Ram 1 ton. I was given a new (in box) audio vox system which says it will work on a 99. However, I have not been able to locate a manifold vacume source on the ISB engine. Is there a source, or did my wife buy me a pig in a poke?

 

[JJMiller]

It will probably work on a '99 gasser just fine! The aftermarket cruise uses manifold vacuum as the force to operate the throttle. Problem is, the intake pressures on our turbocharged ISB's are positive, not negative (vacuum). Your best bet is to find one with an electric solenoid instead of a vacuum thingie (the word escapes me). I know there is a vacuum line on our trucks under the hood, (back by the firewall, up by the windshield, and tucked under a rubber seal ), but I don't know what it's for and I'm not sure it's powerful enough to hook to a cruise system.



Hope this helps.



--J

 

[rubberneck]

There is a vacuum pump on our trucks, as all of the climate control doors and what not are controled by vacuum. I dont see why you couldn't pick up source for the cruise control off of the pump. You could even mount a vacuum reservoir somewhere if needed.

 

[JJMiller]

Ahhh! That's what that line is for. Where's the vacuum pump?



I was under the impression that there was no significant vacuum source on the ISB, which is why the brake booster is powered by the PS pump.



Not doubting you, just curious.



--J

 

[rubberneck]

jjmiller, the vacuum pump is sandwiched between the front accessory drive and the power steering/power brake pump. If you look down there, you will see about a 1/4" diameter plastic line that runs up to the firewall behind the seal you mentioned earlier. It tees off of there and runs in the cab for the climate control doors. If i am correct, there is even a tee in the line with one side capped off. you could take the cap off and get your vacuum source. I believe this is the same way the guys are picking up the vacuum for the exhaust brakes. This is not unique to the ISB. My father in laws 12v has the exact same set up.