Hi there
I searched but didn't find anything with a solution.


front a/c controls look like this


when the front AC is turned on, air blows in the back fine but the lock icon is lit on the rear controls, I understand this is normal.

However, when I turn the bottom left **** to "rear" the rear air turns off and the controls on the rear unit have no effect. no fan, no cooling, nothing.

I found some info elsewhere about something behind the glove box, but when I looked back there I didn't see anything that looked like a relay or something that might go out.

I don't want to just start randomly tearing into things. Any suggestions?

 

still haven't figured this out.

any suggestions?

 

so when you turn the main control to rear, does the lock icon go away? Anything aftermarket up there, like a sunroof or DVD player?

 

When I turn the control to rear, the lock icon turns off, and the air turns off. Turning the rear controls produces no air from the vents.

 

I take that back. When i turn the **** to 'rear' the lock icon stays on.
When I turn the front AC completely off, the lock icon turns off. The rear controls do nothing at this point.

There are no aftermarket electronics that I can find.

I went through the fuse block and pulled anything that said 'hvac.' Everything looked normal. There was one relay which.. I don't know if I'd tell if it was bad or not.

 

So the rear control is basically a slave input to the front control head. When you set it to what you want, the rear control sends a signal to the front control and the front control actually controls the rear functions. So if the lock symbol is on, the rear won't work. Could be the front control is bad or maybe the signal wire is open between the two. Going to be tough to tell without a scan tool.

 

OK, thanks. Sounds like we're off to the dealer for a warranty claim.

 

just as follow up..

finally had time for the wife to take the van in for warranty. Not sure what happened because I wasn't there but the service invoice says:

"Customer staes the rear a/c controls are locked out and can't adjust any settings from the rear controls. system works OK from the front panel.

Scan for codes and vound Code B11D9-92 Blower motor performance
Diag bad HVAC controller. remove and replace controller. clear code. system now working properly."

part number 55111240-AF Control A 24024161

 

Yep, thought so. Had to be an internal controller issue.