The interior blower fan in my IROC runs even with the key off and removed from the car. I have to remember to turn the fan off each time I leave the car. No other car I've ever encountered is like this... is this normal?

I'm not talking about it being stuck on high (which can be caused by the high-speed blower relay), the fan operates normally. It just operates normally even with the car switched off!

Cheers,

ND

 

No, that don't sound right. Something or someone has allowed unswitched power to the fan circuit.

 

blower motor relay is sticking. Tap it with a screw driver. If it keeps either not turning on or staying on, replace it.

 

Checking the wiring diagrams, it does look as though that entire circuit should only be 'hot on run', whereas mine seems to act as though it's 'hot at all times'.

There only seems to be a relay on the high-speed motor function - all speeds (including off) are available on the fan, so I assume it's not that. Unless there's another relay somewhere?

I guess some weird wiring must have taken place to make the circuit permanently live. The AC was removed by the previous owner, if that's relevant? Any ideas where the live circuits may have become conjoined? I'm guessing the blower motor gets its power via the fuse board and the dodgy connection may be under the dash...

 

I'm just telling you try what worked for me. Takes 15 seconds to pop your hood and tap the relay with a screwdriver to see if it shuts off. The relay is the only place it will get constant power from.

 

Not sure what diagrams your looking at - but here's the one for the 85.



Red wire comes off the starter post and runs directly to the high speed relay. I'm guessing that the wiring is hacked or that you need another relay.

 

Yeah, as that diagram shows the high-speed relay is hot at all times, but the lower speeds are supplied by 'hot on run' and power comes through the switch and the resistor, and is grounded through the blower motor. I seem to have all speeds even without the key, which seems to rule out the relay.

Still, doesn't take long to give it a tap with a screwdriver so I'll give it a shot tomorrow.

 

Had a go with the screwdriver earlier. I checked I had all fan speeds (didn't even bother putting the key in the ignition!), then set the blower to '1' and tapped the relays. No change. I've not had a chance to check the Service Manual yet, but I did find two small relays where I expected to find a single, large one... I gave them both a few taps anyway. At least one of them seemed to have wiring conjoined with the blower resistors.

I'll have a poke about under the dash at the weekend if I get a chance, and see if I can find anything in the wiring that looks odd.

 

I've seen more than my fair share of HVAC fan switches that were burned and burned badly,....... I would pull the HVAC controller out of the console and check all plugs to make sure that the fan switch isn't burnt/melted. ( would make me feel better to KNOW the fan switch was not cooked ! )


Edit:

The diagram I posted was from an 85 shop manual. THAT is exactly what your system should look like. Sounds like it's not "factory" anymore.... ?

 

Hello John,

thanks for the advice - I'll pull the controller out some time and take a closer look at the switches. I've already installed relays to stop 12V running through the headlight switch, I was hoping there wasn't anything else I need to do this for too!

I checked my own '85 shop manual, and that also only shows one large relay for the high-speed blower in that location. No idea what the other relay is... it does look factory though.

Hmmm!!

Cheers,

ND