Rear a/c not working

[macdven]

Hi all, I’ve got a 2014 D4 and it came with factory rear a/c option.

I recently noticed (only use rear a/c when kids are in the back) that the control cluster in the ceiling that activates the rear a/c no longer illuminates or functions. And yes - I’ve activated the rear option on the front dash

I’ve checked all fuses, and even LR had a look when the serviced the car - though they said they wanted to remove the headlining to haven a more detailed inspection. I opted to try myself to save $$.

I’ve bridged the relevant relay on the dash and tried for power at the rear blower wires. When I did this, if I earthed the blower power (red wire), I got 14v, but using the red/white in the connector, I got a weird (variable/decreasing voltage - <10v).
Am sure the fuses are good and the relay.

I’m not sure if the switching module in the ceiling runs any power or is driven by a canbus, but there doesn’t seem to be any power running to any if those wires that connect into the 3 socket controlling the three round dials. Does anyone know if there is power and which colour wires I could check?

I’ve heard/read that the fuse block may have poor soldering for the rear a/c fuses. Not sure how to check that.

I’d be thrilled to get any guidance … or hear if anyone has fixed a similar problem.

 

[macdven]

BTW, is there a connection behind the A-pillar trim? I think this was removed to fix hail damage. Maybe they hit something??

 

[f1racer328]

BTW, is there a connection behind the A-pillar trim? I think this was removed to fix hail damage. Maybe they hit something??

I think the connection behind there is for the heated windshield but I'm not 100% sure.

 

[macdven]

I think the connection behind there is for the heated windshield but I'm not 100% sure.

Thanks. I'll take it off and have a look.

If anyone else has any other advice as to why the rear a/c may not be working ... I would be most grateful

 

[macdven]

Thanks. I'll take it off and have a look.

If anyone else has any other advice as to why the rear a/c may not be working ... I would be most grateful

I took off the pillar trim and there’s nothing obviously wrong there - all roaring in tact.

Frankly, this issue has me stumped.

I’ve read elsewhere that it could be the fuse block, but feel this would be very unlikely … and imagine it’s also a pain in the ass to fix.

Has anyone had any experience with issues related to faulty fuse boxes?

The next thing I want to test is the switch cluster/module on the roof lining - the actual fan speed and hot/cold controls.

It takes 2 seconds to pop out. Problem is, I don’t have another to test against. If anyone lives near Warrandyte, and has a D4 with working rear a/c option - and you are happy for me to swap the control and test (would take all of 10 minutes) … lemme know. Pulling out the switch is very easy (pull panel down from the front edge facing front of car, and the slide the models forward. Bingo, it’s out.

Mark.