Rear heat/AC not working?

Hello GRAHAM78,

Does this have rear seat audio control?

If you are not sure you can look on the glove box door or bottom of the glove box for a label. It is filled with a bunch of Alpha-numeric codes. These are Regular Option Code or RPO's for short.

The RPO code that will tell us if you indeed have this option is:
UK6

See if you can find that for me.

There is a technical Service Bulletin that matches your issue, and this will tell me if it pertains to your particular application.

Thank you,
Brendon

Hello GRAHAM78,

I have added the TSB for you. (See image)

Looks like there is an updated module.

Please let me know if you have any other questions.

Thank you,
Brendon

Hello GRAHAM78,

If it's the old part number and not the updated one, then it is subject to the same TSB and could have the same issue.

Looks like you got power back there, but for some reason there doesn't seem to be any communication.

Since you already swapped it with a known good one though, let me take a look and see if I can find anything else for you.

Thank you,
Brendon

Hello GRAHAM78,

Any problems with the front? A/C and heat both work?

All controls and modes work?

Thank you,
Brendon

Hello GRAHAM78,

Do you have any kind of scan tool? If not that's fine.

You can take it to AutoZone or somewhere similar and have them read the codes for you.

See if they can get any codes. They may only be able to access the PCM and no other modules, but it is worth a try.

Any codes that begin with P, B, or U, will tell us if there is a fault shutting down the auxiliary HVAC unit.

Tell them you need to see if you can get into the body control module.

If we can get a code, that will help lead us in the right direction.

Then just have them clear them all.

Let's see what they can find. I will continue working on my end.

Here is a link to some general information about trouble codes for you:
https://www.nonda.co/blogs/news/obd2-codes#: :text=Indicated%20by%20the%20first%20letter%2C%20there%20are%20four,is%20going%20to%20be%20found%20in%20this%20system.

Let me know if you can get any codes.

Thank you,
Brendon

Hello GRAHAM78,

There are a few fuses we should test. I have included diagrams for the fuse box by the Instrument Cluster and Under-hood Fuse Block.

I have high-lighted the fuses you should test using this test:
https://www.2carpros.com/articles/how-to-check-a-car-fuse

This uses a test light and is the best and quickest way to check fuses. If you don't have one, you can get one at your local auto parts store. Sounds like you might though.

I have also included legends for the fuse boxes and highlighted the fuses you will be testing. There are 3. The 2 that are not labeled are for the under-hood fuse box.

Please let me know if you have any questions.

Thank you,
Brendon

Hello GRAHAM78,

So, everything is working like it should now?

Thank you,
Brendon

Hello GRAHAM78,

Awesome! Happy to hear it!

Don't feel bad about the fuse, they are easily overlooked. Especially when they label them with something like ECC.

But you are very welcome and glad everything is working.

If you need anything else just let us know by starting a new question.

Hope you have a great day!
Brendon