blower motor/engine fan malarkey

[tigger]

OK here's an odd one...

A while ago my front heater blower motor was making an annoying noise, so I stripped and lubed the plain bearings in the blower motor before putting it all back together. I should say at this point that the blower was working OK on all settings (apart from the noise on 3 and 4).

The lube seemed to sort the noise. Then at some point afterwards the blower stopped working altogether on any settings. I assumed it was the fuse, but on checking this (and trying a replacement just to be sure) found that wasn't the case. Then on closer inspection I found that, if I put the heater blower control knob onto setting 1 AND press the air con button, the green light on the button comes on and I hear a fan noise. BUT the fan noise isn't the blower - it appears to be coming from somewhere underneath (haven't checked yet, but it must be either the rad cooling fan or the engine bay scavenge fan I guess). On all other blower settings nothing happens - no noise, no green air con light.

So what on earth is going on here?? I bloody hate car electrics! I was going to treat the old Bongo (1995 AFT, had it for years) to a new blower motor, cleaned-out grille/matrix to improve blower airflow, and a new blower resistor pack (can't be doing with bodging it again), but I don't want to splash out until I've figured out what the heck is going on here!

Grateful for any ideas...

Dom

[dom_e]

Is the noise when you switch on the ac the ac compressor? That'd make sense.

[jaylee]

The rad fans will come on with the AC... (At least when stationary.)

Could it be a rear heater/AC blower fan in the back heater unit you can hear...?

[Simon Jones]

Has the A/C been re-gassed recently / ever? I read somewhere that if there is low pressure in the system it will not switch on, but not sure if that prevents the normal fan blower from working? (Wouldn't have thought so). You can eliminate the switch, resistor, fuse side of things by unplugging connector bythe motore & checking if you've got 12V going in.

[mikeonb4c]

The rad fans will come on with the AC... (At least when stationary.)

Could it be a rear heater/AC blower fan in the back heater unit you can hear...?

Yes, and the green light shows you have the aircon button pressed in and aircon activated, as you have correctly identified.

I can't remember the precise symptoms, but it sounds like you need to inspect the front heater resistor pack to make sure nothing has de-soldered due to excessive current and heating (caused by a stiff heater motor being hard to rotate) and/or you need to take the heater motor out and see if it runs when you connect it direct to the battery. Then update us with your findings etc.

There's a fact sheet on repairing the heater resistor - a common problem.

Good luck

[jaylee]

Has the A/C been re-gassed recently / ever? I read somewhere that if there is low pressure in the system it will not switch on, but not sure if that prevents the normal fan blower from working? (Wouldn't have thought so). You can eliminate the switch, resistor, fuse side of things by unplugging connector bythe motore & checking if you've got 12V going in.

Low pressure with the refrigerant gas will just stop the compressor pump clutch engaging with the AC on.. The blower fan for the air duct should still work!

[Simon Jones]

Thanks Jaylee, that's what I hoped it would do

[tigger]

Some good suggestions here - thanks. Clearly I need to investigate further. I'll report back...