Randy V

I get no response when I turn the front cabin blower speed control switch with the output control set to most positions, but the blower does work when in the defrost position. AC does not activate when the button is pushed or when the control is set to recirc.

Fuse checks OK.

Is this a relay problem?

If so, is there a similar relay on the board I can swap to test?

Other causes?

Thanks.

Bill 86.5 928s

Randy....I think you got too much ."Sault"..air in it......

P.S.........How are ya doin... Bill

Alan

Randy - Sounds like the Fresh Air Blower Relay - its a regular type - swap with the horn...

Alan

dr bob

Randy, also check Fuse 37 and the "Supply" relay at position X in the CE panel.


I have a detailed schematic for the '91 -on control head in process on the other screens. Just need to confirm that the head matches the schematic and it will be ready for prime time. Alan, if you could PM your e-mail address I can send a draft of it to you for a look. It's in autocad dwg format if you can use that, or I can PDF or DXF it for you. There are a couple things that puzzle me on this head-- It looks like the fresh-air blower relay seals itself in via a diode in the head, so that once control power from the Supply (X) relay via fuse 37 is in, it closes and powers its own coil until the X-relay drops out. Looks like there's no "OFF" position available on these newest control head versions like there is on most earlier versions. The car wiring to the connectors is the same though.

GregBBRD

Have you offended the 928 gods with some comment or statement? Did you recently swear at your car, with-in hearing distance?

Perhaps you should have gone over and helped the poor guy in San Diego with the intake/noise/needs new engine problem.

6mil928

Would this advice work for a 81 also? Mine is not working either. Jason

rhys

IIRC, if your blower works on defrost and nowhere else, it may be the resistor pack. If you'll run a search on A/C or blower, you'll find a lot of info about it.

Alan

Rhys -

No! it should still work on high speed if the resisitor pack goes out - quite different issue...

Alan

Alan

I am interested in the schematic - I have some also.... The fresh air blower relay goes on via the Supply relay power - just a direct loop thought the head AFAIK (so unplug the head it goes off).

Alan

Randy V

Thanks for all your replies.

I'll take the desert wizard's advice and swap the horn relay as a first step. Thanks, Alan!

Alan

Randy

Try turning your foglights on - do they work? if not swap the Supply relay with the horn relay instead - per Dr Bob - it should be one of these 2.

Alan

Randy V

Fog lights work - had them on this morning.

IcemanG17

Relay is my 1st thought.....its an easy test...swap it with the horn or just jumper it....but since it works on defrost, it makes me think thats not it.....it sounds like the resistor pack to me.....does it work on "4" if it works on 4 but nothing else....then its the resistor (4 is the same as defrost)

Alan

The DEF relay does not use the HVAC supply - it will work with no blower relay...

We already know the fan works in DEF only...

I think Randy knows what he needs to do next... we are waiting on him...

Alan

worf928

Yep. That's is certainly true for 91+. I don't know if the change was MY 90 or 91 though.