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-   -   Interior heater fan/blower not working - no power (http://986forum.com/forums/performance-technical-chat/54687-interior-heater-fan-blower-not-working-no-power.html)

sweatyfox 11-05-2014 09:00 AM

Interior heater fan/blower not working - no power
3 Attachment(s)

Im having trouble with the interior fan blower not working, it was all fine till about a week ago and it just never came back on.

My car is a 1999 Boxster 2.5 (without A/C)

What I have tried so far:
1) Pulled out every fuse and they all looked fine.
2) Removed and tested the blower motor and that works perfectly.
3) Put a multimeter to across the power wires for the blower motor but got nothing, same with the resistor pack.

So I can safely assume there is no power getting to the fan/blower motor.

Where should I start looking next?
Is there a relay for this that might have died?

Iíve attached a few pics of the fuse box/relays.
Also I have no idea what fuse number the interior fan is supposed to be, so if anyone can point that out Id be grateful.

Thanks in advance,


Meir 11-05-2014 12:24 PM

i can have a look in my Bentley book and check out the diagram for the relay, but my guess is you have an issue with the AC control panel.

will post the relay information tonight.

Meir 11-05-2014 04:53 PM

Two fuses for the AC and heater system.

D6 30 Amp
E7 7.5 Amp

Relay 18 (number 1 in your pic) is the AC and heater relay.

sweatyfox 11-06-2014 10:30 AM

1 Attachment(s)
Thanks for the information Meir, I have checked the fuses again which were fine and tried a different relay but still no luck.

So I guess the only thing left is the Control Panel.
What usually goes wrong with these? A fan speed switch? or a circuit board?

Meir 11-06-2014 02:20 PM

sorry i cant help with that as i never came across a non AC vehicle.
the only experience i have is with the electronic AC control module, and comes in one piece.

Meir 11-06-2014 02:28 PM

pic of the electronic control


Meir 11-06-2014 02:47 PM

looking at the PET, it looks like the one you have is a one piece too.
and also do not exist in US&Canada cars.


sweatyfox 11-14-2014 03:31 PM

1 Attachment(s)
Ok, I have a second hand control panel to fit, but can anyone tell me how I get the old one out?

I have removed the 4 screws securing it in place, but I'm unable to pull the control panel into the car as the black mounting tabs prevent it from being pulled forward.

I've managed to have a look behind and there doesn't really seem to be enough room to push it back through and take it out that way.

There's almost enough room to turn it 45 degrees and pull it out the front.

Can anyone tell me the correct way to do this please.


sweatyfox 11-22-2014 09:43 AM

1 Attachment(s)
Ok, so I have managed to remove the heater control panel and refitted a second hand one but still no joy.

What else could be the problem?
The fuses are fine.
Relays are fine.
Fan motor is fine.
Heater control panel has been replaced.

What else is left?

As for removal of the control panel:
This was done by disconnecting the heat and vent position cables at the bottom, this gave more freedom to the cables which allowed me to rotate the control panel enough to be able to pull it out sideways and disconnect the cables and connectors.

sweatyfox 12-01-2014 09:47 AM

Ok, so I'm making progress, but I cant find a wiring diagram that matches my car.

The only wiring diagram I have is for a Boxer with Air Conditioning which I'm guessing is different?

This car has no A/C and is a 1999 UK.

I have managed to power everything up by giving the circuit a 12v + and an earth.
The attached image shows the main 12v power in which is a black & blue wire.

Now here's the problem:
If I just put 12v + to the black/blue wire I still get nothing.
If I ground the motor wire (brown wire - ground) to the chassis nothing works.
But if I do both of the above together the whole system works as it should.

So somehow I the circuit is missing 12v + in AND an earth.

If I had a circuit diagram for this I might be able to make some sense of it.
Anyone have any Ideas to what is causing a 12v + and ground connection to be missing?


Meir 12-08-2014 02:28 PM

sent you a PM

DavidG986 08-13-2015 06:03 PM

Did you find a solution to your problem? Im having a very similar issue. Everything works but blower wont power on.

Dr Feelgood 02-25-2016 08:01 PM

I'm also having the same issue. What was the result of this?

sheldonsmith 04-29-2016 11:16 PM

The blower quit working a couple of days ago - I''ve checked the switch and everything was connected and looked ok, and the fuse for the ''fan'' in the center console fuse box was also ok. I get nothing from the fan, whether it''s switched to heat or A/C.I got confuse what to do then my mom suggested me to contact Heating Service Cypress they came in my home and provide me awesome service,i really enjoy their service.

jedblanks 08-09-2016 07:30 AM

For others that may come across this...

I had the same issue and it turned out to be a relay. Unfortunately I cracked one of the fins on the blower motor when I was removing to troubleshoot. It worked but centrifugal force would cause it to rub as the cracked fin expanded.

Lesson learned: Try the easy things first.

First time I've had a relay fail in any vehicle...

Skullbiker 08-26-2017 07:53 AM

A similar problem - can anyone help
Non a/c 986 2001
Air/heater blower not working .fuses all ok. Relays appear ok. But if I jump the relay posts the air/heater switch works as it should to turn the blower on and off and increase decrease speed of blower. When the relay is in ( tried some I know to be good ) it does not work - nothing,
Anyone got any ideas ?
And - will it do any harm to just have the relay jumped and have the air/ heat switch working in that scenario ?

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