Dennis Burford

Hi all, does the sunroof share share the same relay as the power windows? Both windows and the sunroof will not operate, power seems fine to everything else, including the rear wiper. Wondering if they share the same relay or if I should be looking somewhere else. Thanks.

Mrmerlin

click on this, https://www.928gt.com/default1.htm
then up top on the right view 2,
then on the top left tips and links,
then click fuse relay chart

Dennis Burford

hi Stan, can't find where sunroof gets mentioned in relay chart, but also found out that fresh air blower isn't working, but defrost switch activates the blower. So what's out, both windows, sunroof, and fresh air blower. By chart that would be relays VI and X but separated by VIII relay for defrost which is working. Car has been sitting with battery disconnected for a long while, but everything was working when parked doing timing belt and such.

Dennis Burford

Here's a little more info: I can hear (with my mechanics stethescope) the relays ping when the key is turned on. So now the question is what do these components share that would cause a common failure?

The Forgotten On

This should be a little more clear.
http://928intl.com/repair/Relay/earlyrelay2.htm
The windows do not share a relay with the sunroof or a fuse.
Just as usual clean all ground points and check for corrosion on the
fuse panel. The switches could just be worn out and need replacement.
The issue with the A/C is the resistor pack. It is located inside the HVAC system
behind the evaporator, you need to take off the blower motor to gain easy access to it
and remove the plug that goes to it (similar to 14 pin), unscrew it and pull it out.
Its part number is 928 616 101 00, good luck.

Dennis Burford

This is the relay diagram I have a printout of. Still don't see any mention of sunroof. Window switches are two years old, replaced two years ago at Sharktoberfest. Everything worked when the car was parked, all maintenance was front of engine, with power disconnected at battery ground. Perhaps I will try replacing relays as a start, wouldn't hurt to have a couple spares if they prove good.

Mrmerlin

I would clean the fuses and relays before replacing anything

Alan

They do share a relay (Relay VI in this case) but they don't share a fuse.

Fuse 14 for the sunroof and fuse 15 for both windows - test the top fuse connection (can do with the fuse in - on the ends of the fuse look for the litttle cut out windows...) should be powered with accessory/ignition on - if not its the relay.

Its highly unlikely 3 switches all failed at the same time with no prior symptoms...

If the blower also doesn't work on the max setting (4) then it certainly isn't only the blower resistor pack - so don't order one yet...

It is possible the Blower Relay (relay X in this case) is bad - swap with the horn (if the horn worked before)... what happens?

Alan

The Forgotten On

Alan, in post 3 Dennis says it only blows in defrost position so it is the resistor pack.

jcb928

If the battery is weak it can cause the same symptom.

Alan

NO! - The resistor pack only controls speeds 0-3 NOT speed 4.

Speed 4 is directly driven only from the switch - you can unplug the resistor pack and speed 4 will still work.. so if it doesn't work something else is going on.

Doesn't mean the resistor pack couldn't also be faulty - but it can't be the only thing - simpler cheaper things should always be investigated first.

In this case though I think the resistor pack is likely just fine...

Alan

Alan

I think that's very very unlikely.

Alan

Dennis Burford

Battery is fully charged, speed 4 does work (defrost mode). Fuses seem unlikely but I will check fuses and report back....

Mrmerlin

Dennis on a car that has been sitting for along while its quite possible for moisture to invade the CE panel,
and this can cause corrosion to form ,
so yes fuse cleaning should fix a lot of electrical issues that you not otherwise consider

Note from your post.

Car has been sitting with battery disconnected for a long while, but everything was working when parked doing timing belt and such.

Alan

The question is: does speed 4 work from the switch alone - only that question matters to determine if the blower resistor pack is at fault...

Alan