Weird HVAC problem **evolved to electrical nightmare?

[fatsooo]

So my entire HVAC unit works fine...when the motor is off (key in on position)

When the motor is running, the entire HVAC panel becomes unresponsive as if there's no power

I checked fuse 20 and its still good

But afterwards when I turned the motor off, it worked perfectly fine again.

So here's a quick timeline for clarification
Motor off - HVAC panel works
Motor on - HVAC panel doesn't work at any speed
Motor off - HVAC panel works

Do I literally have a gremlin moving wires when the motor is running? Lol
TIA!


**UPDATE**
Fuse for cig lighter and radio antenna was blown (7.5 amp when should be 30 amp) <- i don't know why this fixed the HVAC problem, but for some reason it did

As suggested earlier (starter not being fully grounded) I ordered the heavy duty ground cable set (since my oil pan ground cable is pretty much toast as well) from a forum member and waiting for them to come in the mail so I can install those as well

Now central locking doesn't work and something is now draining my battery

With the fuses in and no key in the ignition, only fuse 23 is pulling 2.46V
Checked using exposed areas on top of fuses and voltmeter

with the fuses out, I tested where the blade plugs into the fuse box (no key in ignition again) to see how much each are pulling (where things get weird) and these are the results:

Fuse # - Voltage reading
4 - .22v
5 - .22v
6 - .22v
12 - .22v
19 - 11.44v
20 - 11.44v
21 - 11.56v
22 - 11.56v
23 - 11.56v
24 - 11.56v
25 - 11.56v <-thought this was an empty slot
26 - 11.56v <- this one too
27 - 11.56v
28 - 11.56v

I just check fuse 27 (for central locking) and the fuse is in perfect condition
I can't even lock my driver's door so that's not really fun haha

This makes zero sense to me as I'm a noob to electrical work so any and all help is appreciated!
thanks again!

[vpilarrt]

It sounds like switched power is getting applied to the HVAC ground. Check pin #1 on C204 (its the rectangular 12 pin connector just to the left of the HVAC system under the dash on the driver's side). It should be ground all the time (key and motor on or off).

[fatsooo]

It sounds like switched power is getting applied to the HVAC ground. Check pin #1 on C204 (its the rectangular 12 pin connector just to the left of the HVAC system under the dash on the driver's side). It should be ground all the time (key and motor on or off).

Its staying grounded. Wires are brown on both ends but I tested it too

[vpilarrt]

Now I'm wondering about the K7 unloader relay. Do your power mirrors only work with the motor off?

[fatsooo]

Now I'm wondering about the K7 unloader relay. Do your power mirrors only work with the motor off?

They used to work all the time. Not anymore. I'll replace the K7 relay when I'm home and update.

[603Racing]

They used to work all the time. Not anymore. I'll replace the K7 relay when I'm home and update.

+1 Exactly what I was thinking.

[fatsooo]

Now I'm wondering about the K7 unloader relay. Do your power mirrors only work with the motor off?

Just swapped with a known working one, no dice.
HVAC panel no power
Power mirrors no power with motor running

[vpilarrt]

Check the voltages on the K7 contacts in the Fuse Panel (with K7 removed):
86 should have +12V during start and run
85 should have +12V during start and ground during run

[dashboardmonkey]

Sounds like an unloader issue. Problem is in the starter, replace the starter or ground the unloader wire on starter.

[fatsooo]

Check the voltages on the K7 contacts in the Fuse Panel (with K7 removed):
86 should have +12V during start and run
85 should have +12V during start and ground during run

did this real quick before i left for work this morning, 85 was ground full time.

Sounds like an unloader issue. Problem is in the starter, replace the starter or ground the unloader wire on starter.

i will try this once im home from work. which one is the unloader wire?

[jlevie]

I believe it is a brown wire. The black/yellow wire is the the solenoid (START) control.

[fatsooo]

I believe it is a brown wire. The black/yellow wire is the the solenoid (START) control.

Haven't gotten the chance to do this yet.

If it makes a difference, which I highly doubt just throwing it out there, I disconnected the heater valve before this became an issue

[fatsooo]

still havent done the above stated, had other pressing issues with the car so tended to those...but had a weird update tonight

noticed my antenna wasnt working and i needed to cigarette lighter to charge my phone. swapped the fuse (for some reason a 7.5A found its way into that spot) and now my HVAC panel works, mirrors, etc...

is this normal or is there some serious weird stuff going?

[fatsooo]

Anyone? Want to finish up my heater system and its been getting nibbly lately.

Rather do it right the first time

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[fatsooo]

Updated first post. Is it that intense no one knows what's going on? Lol

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