Electrical: Blower Motor Help

[Big 240]

OK. The blower motor isn't working, wasn't working when I bought the car a few weeks ago.

I don't want to just start throwing money at it and replacing stuff for the sake of it, so how would I go about working out what's the issue.

I don't think it's simply the resistor as none of the fan speeds work, so can I hotwire the blower motor directly to check it works?

Or how would I check the switch?

Cheers Guy

[Juular]

Get a multimeter and check you are getting 12v into the switch to begin with (with the ignition on).

If not, trace the wiring back to the fusebox and check the fusebox itself - they're absolutely rubbish on the 240 and get covered in rust. Even when they're clean they're not totally secure, and the bullet style fuses have a tendency to start melting their own insulation with the slightest bit of heat which makes things worse.

Got 12V to the switch? Move towards the motor. Resistor pack may or may not be worth checking. On full power it shouldn't be going through any resistors, so I'd be more inclined to look for dodgy connections or wiring.

On the motor itself, they rarely fail outright, more likely is seized bearings which give plenty of warning in the form of screeching before they start causing issues.

If you pull the stereo out and pull the ducting and mesh out from behind it, you can get your hand in to see if the fan blades move freely.

If they do, you should be able to see the wiring coming down the side of the motor. Either tap 12V in there, or follow the wiring back to a more convenient place and do the same.

If it spins freely by hand but doesn't work, it may need to come out so you can look inside the motor and check the commutator and brushes. Usually it'll be the commutator needing a good clean if it has been standing a long time, or if a brush has cracked or broken up it should be straightfoward to replace.

Getting the motor out.. that's a different story!

[Big 240]

Thanks for the response/advice, I'll have a good check over this weekend.

[Bugjam1999]

Couple of comments, although the advice above is sound.

The headunit could be either at the top or the bottom of the dash - if it's at the bottom, leave it there.

You'll either have a headunit or a cubbyhole above the vents at the top of the dash, remove whichever you have and then remove the vents below to follow the instructions above.

To remove, unclip the clock surround and the similarly sized blanking plate below it, the screws holding in the headunit/cubbyhole and the vents are behind them on the right, they just clip in on the left side.

The motors do give a lot of warning with screeching etc. before failing outright, and the chances are the previous owner put up with it for a while and then it stopped working. Replacement units are available and work well. There's some internet folklore about how awful replacing the heater fan is, and whilst it's a fairly involved job it doesn't require special skills or tools, just a methodical approach to removing everything and then replacing afterwards.

It is possible to remove the heater box without removing the dash completely, but the amount of extra work to remove the dash is minimal and will allow much better access to the heater box, as well as allowing you to check the bulkhead for rust and lubricate the wiper motor mechanism whilst you're there.

Cheers

[Big 240]

Originally Posted by Bugjam1999

Couple of comments, although the advice above is sound.

The headunit could be either at the top or the bottom of the dash - if it's at the bottom, leave it there.

You'll either have a headunit or a cubbyhole above the vents at the top of the dash, remove whichever you have and then remove the vents below to follow the instructions above.

To remove, unclip the clock surround and the similarly sized blanking plate below it, the screws holding in the headunit/cubbyhole and the vents are behind them on the right, they just clip in on the left side.

The motors do give a lot of warning with screeching etc. before failing outright, and the chances are the previous owner put up with it for a while and then it stopped working. Replacement units are available and work well. There's some internet folklore about how awful replacing the heater fan is, and whilst it's a fairly involved job it doesn't require special skills or tools, just a methodical approach to removing everything and then replacing afterwards.

It is possible to remove the heater box without removing the dash completely, but the amount of extra work to remove the dash is minimal and will allow much better access to the heater box, as well as allowing you to check the bulkhead for rust and lubricate the wiper motor mechanism whilst you're there.

Cheers

Thanks, I actually am looking forward to taking the dash out if I need to, I have done this on nearly all my previous cars haha

[Moomoo]

Originally Posted by Big 240

Thanks, I actually am looking forward to taking the dash out if I need to, I have done this on nearly all my previous cars haha

I’m going to keep you on file for the future!😁🤔👍

[Juular]

To be completely fair, taking the dash out of the 240 was one of the easier jobs in restoring mine. It only took about an hour. As mentioned above it's also a good way to combine lots of maintenance, such as descaling the heater matrix, checking and sealing leaks from the windscreen seal or whatever else.

[Juular]

This is the guide I followed. My '88 was very slightly different but to be honest it's all fairly straightforward stuff.

http://cleanflametrap.com/dash.html

And for the motor itself.

http://cleanflametrap.com/fan.html

[Big 240]

Originally Posted by Juular

To be completely fair, taking the dash out of the 240 was one of the easier jobs in restoring mine. It only took about an hour. As mentioned above it's also a good way to combine lots of maintenance, such as descaling the heater matrix, checking and sealing leaks from the windscreen seal or whatever else.

Exactly my plan, check all the stuff that can cause headaches further down the line. Luckily the car has been very very well maintained before I got it. So I'm hoping most things will be preventative rather than required..

[morsing]

Originally Posted by Juular

And for the motor itself.

http://cleanflametrap.com/fan.html

American fan motor, very different. Whole heater setup is different.