Spun

So my battery has been draining the last week and I have not been able to run down why. I was reading this thread and decided to check https://rennlist.com/forums/928-foru...defroster.html

I went out and played with my rear defroster and it does not light up at all. Bulb could be burned out, but it was non in the on position before I played with it.

When i was about to get out and discount that as an issue, I noticed the AC light was lit up. I then listened and could here the fan blowing just a little. I turned the fan up and it blows. Keys out, car off, etc...

I tried to run this issue down through old threads and did not find anything similar.

Anyone know know whats up?

It like these two 89s are jealous of one another. I fix one thing on one and some happens on the other... sibling rivalry I guess "pay attention to me me me"

Thank you in advance!

Mrmerlin

remove one at a time the HVAC relay then the blower relay one of them is sticking on after the key is removed might take a few tries to get the relay to stick on and figure out what it is.
Once you find the offending relay replace it

WallyP

You turned the rear defroster on...

Make sure that it is turned off, then start the engine. When you turn the ignition off, all should be well. The rear defroster relay sometimes stays on with the ignition off.

Spun

I did that last night and it did not change anything, but I will give it a got again once I get the battery charged again (@#$ #$@$-#$).

From a positive standpoint, I am getting to use my charge far more than I thought I was going to. Looks like that was a good upgrade/purchase

Will do.

I do recall I turned on the rear defroster when thelaurie and Dale (the guy that purchased my 79 5-speed) were in the car on teh way to teh Tool concert. That is when all this started .... I shuld really try sleeping at night and not working out the bugs on my cars This is when all this started.

I was wondering if it was another symptom of "magic blower", but mien blower works at each setting.

Alan

No nothing to do with magic blower, defroster is a possibility as is a failing ignition switch. When the HVAC stays on wiggle the key/switch. When HVAC stays on w/ key off - do the foglights also work?

Alan

Spun

OK, I pulled I/II (Rear Window Defrogger) first.. no change, then I pulled VIII (Defrost) . It turned off. I did not get to the fresh air blower (X), so I am going to assume, for the moment, it is VIII. I did pull VI (window winder) to get to VIII, but I cannot think how that would play at all.

I did not see any of the others that would be a player:

I/II Rear Window Defroster
III Nothing
IV Ignition Relay X
V Indicator Flasher
VI Window Winder
VII Wiper delay timer
VIII Defrost
IX Supplementary Cleaning System
X Fresh Air Blower
XI Interference Suppressor
VII Twin Tone Horn
XIII Fog Lights
XIV Starter
XV Kick-down
XVI Electronic ignition system
XVII Antilock braking system
XVIII Cooling-air flap adjustment
XIX Headlamp washer system
XX Fuel Pump
XXI Interior Lights
XXII Reversing lights
XXIII/XXIV Headlight System
XXV LH-Jetronics
XXVI Nothing


Any thoughts. I am still waiting for the car battery to charge enough to crank. I am guessing about an hour like the last 2 times... aurgh

Spun

Did not try that yet. Once I get her fired back up, I will stick the relay back in to see if I can repeat this event with the fog lights as well.

I am reading the HVAC Heating/Ventilating/Air Conditioning trouble shooting right now http://www.928gt.com/T-WallyHVAC.aspx

... OK, pretty sure that is not the issue.

Mrmerlin

I had this issue with my 88 it was a bad relay for HVAC system,
I dont remember if it was the HVAC or the blower relay,
but it was exactly as you described it replacing the relay restored function

SeanR

The two times that I have seen this, it was the ignition switch.

Spun

OK... car fired backup and played with the relay. Problem stopped with the relay out.

I put the relay back in and also no longer an issue. I did not fiddle with the defroster and try again. As far as I can tell, everything works as planned... less the rear defroster which I could not tell was working anyhow. I am keeping the relay out for now.

Thankfully I live in the desert and I think I have needed a rear defogger/froster once in 20 years. This will be a 928 50% off sale wait

Thank you gents. I was pretty sure it was not the ignition due to no change in status as I played with it. I have had ignition issues on many other vehicles that I mostly discounted that here (though on the 928 I am pretty sure you cannot discount anything until everything works).