Chazz

The blower on my car recently began operating intermittently and eventually stopped completely. After about a week of studying the circuit diagrams, with the help of Alan's excellent concordance, and crawling around the car with multimeter in hand, I decided the control module was the likliest source of the problem. It turned out to be contamination on the slider switches in the module. A good wipedown with mineral spirits and averything was OK. To clean it you have to pop it open like you do for the air conditioner relay repair.

The view inside my side panel looks exactly like yours - what the heck is that green open connector?

bfellows

Green open connector is to sunroof rocker switch. Blowers are all working fine, as is air con. I intend dropping the fuseboard tomorrow to check for any shorts and tidy PO hatchet jobs. Even with the console and all controls pulled if I short out the cigarette lighter the relay still clicks! HELP!!!!

bfellows

Thanks to all for the input so far! Pulled the fuse board and found this disaster waiting to happen!

Short Grey cable jumped from incoming power window feed to relay melted on rear of board.

Two cut cables are all that remains of window rocker switch connector (melted into the female connector.)

Rocker switch cut and joined by PO shorting out - PO fix, stick in a 30amp fuse!

I have replaced the grey cable, checked and changed all fuses for correct rating, replaced power window switch and cable assembly and have stripped back the loom to expose the damaged cables. Good thing, as the cables have degraded along their length meaning I will have to bypass the originals and route in a replacement cable.

Ironically, I still haven't found the cause of my original problem - fans coming on when I press the cigarette lighter in!

SharkSkin

There may still be a melted wire in there that you haven't found yet -- keep poking around, looking under that spaghetti mess on the back of the panel...

928SS

strange things happen w/these beasts - I had an interior roof light that was mis-wired, and when the car was in gear the door chime would come on!!! apparently, if one supplies power to what should be a ground, stuff can magically be activated like a haunted house.... my guess would be to ck the fan grounds and see what else is grounded there.... maybe the lighter is just wired backwards??

Alan

Bert - WOW Talk about the PO from hell.... Thats got to be a concern - but at least you are working through it methodocally... eventually you'll get it back into shape.... step by step

Your PO obviously vastly overestimated his electrical knowledge!!

if you need any pointers on R&R for the Central Electric panel - let me know... I can tell you where to get terminals that will work for the relays, plugs/sockets and fuses - hopefully none of the terminals embedded into the CE panel are fried (the double blade types - front & back) once that happens repairs are hard.

Alan

bfellows

Update: Stripped out most of the loom in order to replace the Power window feed and earth which had melted near enough there entire length - What fun......

Still can't figure how the cigarette lighter can be kicking in the fans? If I pull the 25 amp fuse then the problem is gone. I've now stripped out all of the live side wiring to the cigarette lighter and it is all in good condition. I checked for breaks and can confirm that it is not going to earth. Somehow I think the lighter is back feeding to the fan controls? I've checked all the wiring diagrams and can't see how?

Time to call in an auto electrician?

Alan

Bert,
I'd suggest you pull the blower relay - does it still do it? if yes its a wiring issue - if no put it back and pull the fuse for the blower - does it still do it?

If it seems to be the wiring you will have to do some hunting - unhook the battery and check with an ohmmeter between the lighter & the fan wiring?

If its the relay then either the relay coil ground or the coil feed could be suspect - with the battery un hooked test the 85/86 terminals connections and resistance to the lighter socket

BTW does the lighter work correctly?

Alan

Imo000

I've got an easier fix for you. Use a propane lighter!

928autobahndreamer

Or better yet don't smoke in your shark.

Mrmerlin

Hey bro on a hunch try pulling the #V relay its for the ignition also look very carefully at all of your other relays and make shurwe that they are not corroded both on the pins and around the edges of the relay covers if any look like they have corrosion open them up and see what it is, also make shure you have all of the correct relays in your panel and check the resistance group in the blower duct for the correct part number that is under the hood and next to the the wiper motor it is the big plug , Goodluck, Stan

bfellows

Thanks for the continued input! I will check out the suggestions tomorrow (thought i had better do some work today as i've already spent 4 days on this!) Auto electrician is already booked for Tuesday just in case! All the relays are factory fitted and never been pulled as far as I can tell and cigarette lighter is working.

Stan, the ignition relay #V does pull in when I short out the cigarette lighter, not the fan relay! Am I missing something? Is there a diagram in the WSM that shows numbered terminals?

As for smoking in the Shark..... never have done, I leaned over the lighter to drop the keys in the ignition and pressed the lighter in error!

bfellows

Latest update:

Pulled the blower relay and the fans still kick in, if I pull the fuse - no fans.

After pulling most of the relays I can confirm that its relay VIII (defroster) that is pulling in when I short out the cigarette lighter - If I pull the relay, no fans. I'm assuming then that the problem lies in the defrost circuit?

On the positive side (no pun intended) at least all of my earthing points, fuses and relay contacts are cleaned.

May be time to make a long overdue offering to the hallowed shrine of the 928.....

Alan

Well certainly starts to narrow things down...

Do the same tests I mentioned on the coil contacts for the defrost relay. This relay kicks in the fans on full when you select defrost (DEF) on the slider. That is exactly what it is supposed to do.

This mode gives you instantly: AC on MAX, windshield air selection and blower on max.

Value - this is the fastest way to demist a windshield. It really works too... I know...

(I once had the windshield fully fog up instantly in a sudden downpour on a sunny day (wierd)
going @~70MPH & unable to see the road is not a fun thing... DEF mode cleared the windshield in about 3 seconds (a very loooong 3 seconds. No damage but one of those real "oh Sh*t" moments).

Anyway - swap the relay out - its a regular SPST type so try another equiv.
Test the coil connections.

Why not just rewire the lighter socket - its pretty simple
or pull the DEF relay (means you have to manually do fans on high for that case)

BUT -I once would have said that feature was only a gimick - but not any more....

Alan

bfellows

Finally solved my "aircooled ashtray" problem...... and I'd like to thank the PO for all his / her hard work in butchering the wiring! Turns out that the cigarette lighter was finding its way to ground via the defrost relay as it had nowhere else to go!

After deciding that enough was enough (3 months with no real progress) I decided to strip the old wiring completely out of the loom. At this point I notice the loom tape around the earthing point under the steering column is loose and non OEM so decide it will be a good place to start when sure enough after beginning to strip back I find two neatly cut wires!

Problem solved! Just got to get the dash put back together now.

My thanks to all who have offered advice, "first check all your grounding points" is etched into my mind forever as some of the best 928 advice around.

Regards