Z35 heater help. No codes, resistors recently resoldered. Won't turn on.

Last month I had time and resoldered the resistors on my aux heater and was able to clear the codes and command it on.

Car was able to turn on the heater as well on a test drive.

Now, z35 heater won't turn on either with vcds or during warmup with the parameters met (cold air temp, cold collant temps etc.)

No faults found on the aux heater with vcds. I've checked the power wire at the fuse box and cleaned the corrosion that was around it. I have continuity through the 100amp fuse on the power side.

I'll check the power and ground connections at the heater next.

Any ideas?



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My guess is that you make sure it is commanded on. The measuring block for the Z-35 will tell you if it is indeed working. After that, I would have to do some head scratching. IIRC my Z-35 showed either watts or percent when it was operating. Are there any output tests for the Z-35? One possible is that the CTS is defective, so check CTS with the car stone cold and at operating temp.

Yeah unfortunately the measuring blocks said heater "ON", but zero amps and zero watts.

Battery voltage was 14.5 at idle.

Will check wire connections at heater next.

Peter


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wiring looks tight.

I can get the heater to turn on for about 30 seconds with the vcds or the car... but it's not reliable. If I rev up the engine to about 1500rpms, I can get it to output 75+amps and 1000w.

I had my wife take me out on a quick test drive and the heater quit before we were out of the driveway. Coolant temp was under 20C, air temp was 5.5C.

...

I was digging around for faults and found this intermittent one with my HVAC system.... see below.... Now to figure out how to fix it....



Address 08: Auto HVAC Labels: 1K0-820-047.LBL
Control Module Part Number: 1K0 820 047 DQ
Component and/or Version: Climatic PQ35 090 0505
Software Coding:
Work Shop Code: WSC 00000 000 00000
VCID: 76E3326F017A9CFAFF-8022
1 Fault Found:

01207 - Control Module for Auxiliary Heater (J364)
004 - No Signal/Communication - Intermittent

fixed.

Here's what I did.... Best part, no parts fired from the parts cannon.

I had good continuity between the labelled wires at the aux heater and the can gateway.

I had a good ground... just a tiny bit of corrosion on a different lead that was using the same ground. Cleaned it up with some emery paper.

Still intermittent functioning of my aux heater. I.e. would work for about a minute and then stop producing heat.

... decided to go into the can gateway module with my vcds and I disabled the radio as I had just put in an aftermarket Android unit with an aftermarket (Scorsche (sp?)) Can bus adapter., but that meant that my radio wasn't turning off with the ignition... I decided to 'reboot' or 'reset' the canbus by saving the stock values to it....

Seems to have worked. Aux heater is staying on until the coolant temp reaches 75C, and heat is demanded. The VCDS can turn the aux heater on, and it will draw 50+ amps at idle.

I think I may have caused the problem a couple days ago when I was fooling around with the "v68" temperature flapper motor. I needed to remove a module in order to move a bracket and access a hidden screw while working in the driverside footwell (yeah fun). That module ended up being the CAN gateway I believe. Probably wasn't an issue until I attempted to start the car twice and it wouldnt run because the CAN gateway was disconnected. That may have been the cause of my recent Aux heater problems.

Can't wait for a cold morning start... 1st time with an auxiliary heater functioning, and no glow plug errors!

Not fixed.

Had doubts that aux heater was working reliably, scanned it again on Monday evening and got intermittent faults under 7d

My soldering job on the resistors doesn't seem to have held up. I have ordered a lighted magnifying glass from Amazon and will try again next week.

... Ahh, the life of an amateur shade tree mechanic.

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