Erling G-P

Have a question I hope someone can shed light on.

I want to pull out my radio to check the connector on my A/C button as described in this thread:
https://rennlist.com/forums/928-forum/363152-dead-ac.html

My A/C also stopped working, with no light in the button, and this time it isn't the fuse.

However, I got the repair manuals downloaded last week and while browsing them, I'm almost certain I saw something somewhere about the radio having to touch something/be connected to something when you installed it. Be damned if I can find it again though. Does this ring a bell for anyone, or have I imagined it all ?

P.S. Radio is not the original one.

Cheers,
Erling

joejoe

As the radio is slid into position there is a bracket that holds the rear of radio in position (at least on OB's) The light in the switch can burn out also. Some careful disassembly is required to replace.

Rocha928

With the correct tool, radio comes out very easily.

If you look closely at your radio you should see 4 tiny holes at each corner. The tool is two u-shaped pieces of wire that get pushed into these 4 holes. I believe the tip of each wire's end has a notched grove. Push tool in, it clicks, then pull out radio that is now attached to wires. Not sure if I explained that well or not.

Perhaps you can check out a local auto parts store and see if they have this tool, or maybe a Best Buy or Circuit City? The tool worked on my stock 1986 Porsche radio and aftermarket Blaupunk.

Good luck,

Erling G-P

Thanks guys, just had a go at it.

Joe: unfortunately, it isn't just the light in the button; the A/C isn't working anymore. Also, engine cooling fans does not come on when you press the button, like they did when the A/C worked.

Rocha: got those u-shaped braces, but radio won't budge. I can loosen it a little in the right side, but left one seems totally stuck. Are there any tricks to doing this other than clicking braces into place and then pulling them ?

Cheers,
Erling

Shark Attack

what kind of radio is it? If it is a blaubunkt, it came with some special removal tools (that you can make) if it is a Blau.. I will go snap a few pix and post them.

The connector for that ac button can be pulled off easy when the radio is slid in place. I think this is what happened

joejoe

Remove the 2 side panels and push from behind. Is system charged?

Erling G-P

Thanks again guys.

Shark Attack: It's a VDO Dayton radio/nav system.

Joe: I believe the system is charged, unless it's suddenly lost it. Was working fine before, with the limitations brought by the ventilation fan having seized.

Cheers,
Erling

Jim M.

See if the compressor is turning. We usually see a high resistance in the relay contacts. With the compressor clutch coil disconnected, the current in the circuit is almost nothing, and the resistance causes virtually no drop in voltage on the clutch circuit. Connect the clutch coil and the current requirements go up to about 6 amps, and the voltage drops due to the contact resistance. The key is to do it with the load (compressor clutch coil) still attached. Find the anti-freeze switch at the base of the windshield. Square 2"x 2"block, with two electrical connections and a capillary tube, mounted near the center of the car near the A/C tubes. Turn the ignition and the A/C on. If you get 12V and the clutch clacks, your problem is elsewhere. If the voltage is less than 11VDC, and the clutch doesn't clack, either the blue relay or the anti-freeze switch is bad. With the clutch hooked up (no disconnected wires) check for 12V between each of the electrical terminals and a ground. You should get 12V on both. If you get it on neither, the little blue relay may be bad, or the problem may be between the relay and the central power panel. If you get 12V on one connector and not the other, the anti-freeze switch is bad. A simple series string, just find where you’re losing the voltage. A good relay will have 12V; a weak relay will have much less. If you get low voltage, double-check by pulling the connector at the compressor and check again. If the voltage comes back up with the clutch disconnected, the problem is the controller relay. The A/C switch powers a relay in the HVAC control head, behind the temp sliders. See [URL=http://www.928oc.org/tip/tip055.htm [/URL] for the PDF file for a drawing and instructions on the job. I used a Radio Shack 275-249A it’s a 12VDC 5A 240VAC/24DC, single coil, double throw relay with a higher current capacity or Radio Shack 275-218C. It’s a Siemens/Potter Brumfield, # K10P-11D15-12. The coil resistance is 160 ohms, with contact rating of 15 amps @ 30VDC. The original Gruner 202 relay has coil resistance of 230 ohms and contact rating of 2.5 amps @ 250VAC. The compressor clutch draws about 3.5 amps @ 13.5V so it’s no wonder the contacts fail. Wire it per the drawing on Greg Nichol's website. The connections per Dr. Bob's numbering on the A/C board: 1 on board to 4 on relay, 4 on board to 3 on relay, 5 on board to A on relay, 6 on board to 6 on relay, 7 on board to 5 on relay, 8 on board to B on relay. Clearance is tight so be sure there’s enough room before finalizing the mount location. The parts are under $10. and takes about 2 hrs including R&R of the HVAC control unit. A rebuilt unit is $300! The new relay is more robust than the OEM one. You need some soldering skills to remove the old relay and attach the connecting wires to the new one.

Jim Mayzurk
93 GTS 5-spd

Erling G-P

Thanks a bunch Jim for the thorough writeup. Fear it may be a bit over the top for my non-existent car mechanic skills, but I will at least try to find out if the compressor is turning or not.

Cheers,
Erling

Alan

Erling - to get the radio out - put the u shped pins in and take off a side panels as noted - the passenger side is best - easier to get to and once out also easier to get to the back of the radio. Feel in the carpet for the 2 screws on the side - down @ about seat level - you will also have some other screws at the top/forward end - it will be obvious. Once its off push the radio from behind and pull from the front...

Check the plug on the back of the AC switch first... also check the connections on the AC head unit (2).

Alan

Erling G-P

Thanks Alan, will try the sidepanel approach when I get home from work.

Had an auto-electrician looking for faults last Tuesday (of course the car behaved exemplary, except for the fan seizing, so he didn't find anything) He had the passenger side panel off, so I'm hoping he perhaps bumped the A/C connector accidently. The A/C head unit you mention, do I find that in the console, or maybe somewhere in the engine room ?

Cheers,
Erling

Erling G-P

Have just had a go at the car.

Radio remains where it is; can't get it out. Removed right side panel, but that only allows me to push the right side of the radio from behind and it's the left that's stuck. Can't get my hand in behind it, as the space is filled to the brim with cables and plugs etc.

Left side panel seems considerably more boxed in by the undertray above the pedals, so didn't attempt to get this off.

Tried spotting the A/C plug from the right but couldn't get my head in the right angle as the glovebox was in the way. Tried a small mirror and a flashlight, but too difficult when you don't know exactly what you're looking for.

Used up all my swear-words reattaching the side panel, trying to get the screws to match up with the holes. After succeeding, I realised I just might be able to spot the plug if I had my head all the way down at the fuse panel. Off again with the side panel (even more troublesome getting back on the 2nd time - I need to learn to swear in more languages than Danish, English and German combined... )

Spotted a fairly large, blue, rectangular plug with a lot of empty sockets in it. It appeared to be firmly in place, so there goes the easy solution, if it was the right one I was looking at.

Nothing moving in the engine compartment btw, with ignition on and A/C button pressed.

Thanks again for the suggestions and help guys; must see how deep into the more advanced trouble-shooting I dare go.

Cheers,
Erling

Alan

The AC head unit is behind the fan & slider controls on the console (the controls are part of it). You can remove the trim (H shaped piece) around the radio & AC unit and then unbolt the AC head and the AC switch & central locking panel from the front. Then they come out forward out of the console.

Getting the H shaped part out is delicate - easy to break - but actually not hard once you've done it. Maybe someone else can describe how - Its been a long time since I last did it.

You will need to do this to check the head unit dual connectors and to work on the AC compressor relay (if needed) Of course this way you can check the switch and replace the bulb if needed too.

Did you try the DEF mode (slider) - does the compressor come on then?

Alan

Erling G-P

Thanks Alan, Think I saw a description about how to remove the trim in the workshop manuals, so I'll better take a look again.

Didn't try the DEF mode this time around, but think selecting DEF a few days ago may have been what killed the A/C !

Ventilation system in the car seems pretty screwed - selecting 'recirc' blows the A/C fuse (#37, 7.5A). Selecting 'DEF' has so far given me a furnace-hot blast of air in the face (while the fan still worked), even with the temp slider at the coolest position. Is this normal behaviour or a sign of something wrong ?
The outside temp readings in the info display are way off - showing below zero temps in the middle of summer (no, even in Scandinavia it's not usually that cold in July.. ) I've been wondering if this is perhaps why I get hot air in 'DEF' mode.

Last time I selected 'DEF', in heavy rain but after the fan had seized, I still got hot air, but heard some 'noises' from the console and when I next tried the A/C, it was dead. May be a coincidence of course, but gut feeling tells me it isn't.

Cheers,
Erling

Alan

DEF mode should not give you full heat to the face

It should be warm-hot - but not as hot as full heating. The DEF mode is for defogging the windshield.

It automatically ignores the temperature slider + sets full heat (for heated drying) and full AC (for dehumidification) at the same time + set blower to full + selects the windshield vents and I believe selects recirculate mode.

It sets AC on regardless of the switch.. which is why I suggest it as a switch test.

You seem not to be getting the right vent selection and it seems the AC is still inoperative in this mode for you to get full heat...

Alan