timabe

My front blowers (left and right) have suddenly stopped working. Here is what I've found:

- CCU gets power as the lights on the AC and Recirculation buttons light up when pressed.
- Fuses 1, 28 and 17 are good.
- Relays are good (swapped them out from a known working 993)
- Pulled CCU and tested pin K2 (ground at K1). Full power.

At this point I'm stumped. I'm inclined to blame the CCU, but I know failure is rare. Anyone have any other suggestions?

Paging Tore!

IXLR8

Have you checked the levels at the Blower Final Stage and the connector to it?

timabe

How and where do I check the blower final stage? Thanks.

IXLR8

Remove the plastic trim that covers the area behind the fuse/relay box; the cover over the blower motor area. Remove the rubber molding first; it is pressed on.

Right behind the fuse/relay box and slightly to the center is an in-line connector with a series of wires pointing straight up. The unit it plugs into is on a metal plate held in place by a couple of screws.

Sorry, I don't have any pics of that area...yet.

PM sent.

IXLR8

Here you go.

timabe

Thanks for the help Alex. I'll check tomorrow afternoon.

ToreB

I would also suggest that the final stage is blown. It's repairable, but I haven't got the details on this. There's some additional info on the location and how to get to it here.
Cheers,
Tore

timabe

Found the problem. The fuse connection at 28 (rear blower) was weak. The contact was pushed down JUST enough to miss making contact with the fuse. If the system senses the rear blower is not functioning it will not allow the front blowers to operate.

When I originally tested fuse 28 with my voltmeter, I must have been pushing down hard enough with the lead to once again make contact. After I tested the fuse and connection once (and both tested good), I moved on to start testing more complex issues.

I slightly bent the fuse, replaced it, and it made tight contact and is holding. Blower is blowing and my windows are no longer dangerously fogged up. Woo-hoo!

vincer77

My front fans will momentarily shut down when on ac and high setting. Would this be a fault with fans our ccu?

ToreB

Great news timabe! Congrats finding the problem!

vincer, the front fans shut down when there's a problem with the rear fan. See my DIY page for details.

Cheers,
Tore

vincer77

Thanks for that page Tore! As I understand it, the rear fan is used for heating. Mine does this on ac - not sure if it does it on heat. T

The Brewmeister

Sometimes those little victories are the sweetest!

ToreB

The rear fan is only used for pushing heated air yes. The temperature **** will control the amount of heat. It's perfectly possible to need heated air to the cabin with the A/C buttons ON. When you write "being on AC", does that mean that you have the temp **** set to minimum?
If not, will the rear fan operation be dependant on cabin and ambient temperature.

But, the rear fan has two purposes, one is pushing heated air, the other is to cool the engine at ignition off or at minimum temp setting. See my DIY page for details in this.
Cheers,
Tore

timabe

True that. This one was driving me (and my wrenching buddies) NUTS. It just didn't make sense. Only after retracing my steps for the 10th time did the problem reveal itself. This all started when I started screwing around with the fuse box adding a couple of switched connections for my V1 and accessory plug. Now that everything is working I'm not touching the fuse box again (if I can help it).