When I start my truck, I hear a vacuum leak at the climate controls. I pulled it apart today, and the spring-loaded block that slides side to side is not sealing. I cleaned it up (had all kinds of gunk/dust on it), and cleaned the inside of the housing, but it still doesn't seal. What is that block called, and has anyone had a similar experience?

 

Bump.
I don't have a dealership close by (the bailout killed the local one), and don't relish paying a Mopar price. But, I also don't want to pay Ebay prices on a used control unit, to get the vacuum block off of the back (which more than likely will be worn out, too). Hopefully, someone has gone through this...

 

The second gen trucks mostly have a rotary vacuum control, what you are describing is the first gen control which must have carried over. I know that even the very early second gen trucks that had a push/pull cable to control the blend door even had a rotary vacuum mode switch so what you are looking for is very unique, you might try a used first gen control and see if it works. If you get a chance I would like to see a pic to see how they used that style of vacuum mode selector switch, they were very creative with the use of the push/pull cable for the blend door.

 

Doing an ebay and a car-parts.com search showed it being used from 94-97. Photos varified that mine is the same. It is a rectangle plastic piece that has teeth on the bottom; when you rotate the dial to select where you want heat/air to go, it slides the block across the vacuum holes. The block is spring loaded, with a rubber pad which contacts the back of the housing (where the vacuum ports are). It has a block design in the rubber, which seals corresponding holes for vacuum passage. I am assuming that either the rubber has worn down to the point that it won't seal completely, or the spring is weak, or there is enough wear on the back of the plastic housing that it isn't sealing well. After a period of time, it stops leaking. I should have snapped some photos while it was apart, but you can see the unit in this ebay posting- it is in the third photo, to the right- the black case with the cut vacuum lines. Mine is identical.
http://www.ebay.com/itm/94-97-DODGE-...392dea&vxp=mtr

I've done some more searching, thanks to the part # in one of the photos on the ebay listing. The same control is used in the 94-97 trucks, and it runs about $170 or so new. I can't seem to find the sliding block seperately.

 

Thanks for the link.... when I installed the AC into my new 2001 I got the controls from what I thought was a 1995/96 1500 that had a push/pull cable blend door, I used that vacuum mode selector switch to replace my non AC switch I also used the front switch panel into which I inserted the electric blend door control and new fan speed switch. The front panel was the same as my 2001 except it had AC and MAX AC positions, so perhaps they changed the 1500 around then.

 

94-97 temp control has a square, flat face (interchangeable 94-97).
98 is somewhat rounded/countoured face with rounded corners. Looks like a 99-02 on the front, and like a 94-97 on the back. (interchange is 98 only).
99-01(02) are interchangeable and the face looks like the 98. These do not have the gear on the back side like the earlier ones.

 

You forgot to mention you probably have at least one of each and a price!!

 

I ordered a new control unit, and installed it today. The leak at the block had gotten worse, plus when I pulled out the vacuum hose cluster, some of the lines had enough abrasive wear That they were leaking vacuum. It is all good, now.

 

how much do they go for?

 

I paid $148.00.
http://www.ebay.com/itm/New-O-E-M-Mo...79f878&vxp=mtr