I have a 1974 XJ12L that I am restoring. I have the dash and dash cover off, and have found the defrost ventilation control boxes are falling apart. The plastic seems to be deteriorating. I have not been able to locate replacements for these items. (jag P/Ns C38997 & C38998)
Does anyone have any ideas where I could find these either new or used? Are later XJS units similar to the early XJ6/12 ones allowing retrofitting? Any help in this matter is greatly appreciated.

Submitted by zurdo_1@univis… on Thu, 04/26/2007 - 09:28

Edited on 2007-04-26 16:45:00

wow, I didn't know they could get like that...

the one I have has Part Number CAC 3170 RH (Right Hand side) stamped on it, it's from a Series 3 XJ. It measures 10 and 7/8 inches side-to-side, by 4 and 1/4 inches across, by 2 and 1/4 inches high. all measurements at their maximums. It looks similar to yours, I just don't know if the measurements are the same in yours. Mine must be the "Newer and Improved" variety. (picture below)

the plastic housing is like new, the metal "door" has surface rust but is sandable and paintable black.

I also have the foam "gasket" which is glued on top of this housing and seals around the dash's vent opening, and the vacuum valve which is missing one of the three small mounting screws.

Submitted by zurdo_1@univis… on Thu, 04/26/2007 - 09:24

wow, I didn't know they could get like that...

the one I have has Part Number BAC-3170-RH (right hand side) stamped on it, it's from a Series 3 XJ. It measures 10 and 7/8 inches side-to-side, by 4 and 1/4 inches across, by 2 and 1/4 inches high. It looks exactly like yours but I don't know if the measurements are the same. (picture below)

the plastic housing is like new, the metal "door" has surface rust but is sandable and paintable black.

I also have the foam "gasket" which is glued on top of this housing and seals around the dash's vent opening, and the vacuum valve which is missing one of the three small screws.

Submitted by tcaron2979@cha… on Wed, 04/25/2007 - 20:02

Thanks for the reply. Yes the description you have offered is accurate. I have enclosed one image of the worse of my two units (passenger side). I'm not sure how much you can tell from this, but the assistance is greatly appreciated. T.C.

Submitted by zurdo_1@univis… on Thu, 04/19/2007 - 08:01

do you mean the "boxes" that have a small vacuum valve on one end, located on each side of the top of dash, and each has defrost "doors" which open by vacuum? if you post a picture here I'll compare it with a used one that I have from a later car.