Heater blower goosed?

[PhilH42]

caduceus said:

Thanks Steve. I tested the connections with the current setup and nothing. So then I removed the 12 amp (glass) fuse and tried again and the motor whirred into life! Maybe the fuse is gone, but through the glass there is no apparent break.

So, I have taken the heater control module ends off. There seems to be no immediate burnout residue or major rust. There are no wires inside the module so nothing to check on that side of things.

I'll go back out and plug the plugs back together, connect up the battery, and then check the green for power at the end where it plugs into the box inside the dash.

Does the ECU need to be connected for the fan to work?

Just as a heads up...don't write off the pcb inside the module casing as being all ok, mine had no evidence of an issue or scorching but I swapped the unit for another and that was the problem. Is there anyone close to you who has easy access to their dash top so you can try a quick swap?

[caduceus]

PhilH42 said:

Is there anyone close to you who has easy access to their dash top so you can try a quick swap?

No

[caduceus]

I just tested the plug which plugs into the heater control module and there is no power getting to it. I tried the green and yellow, then ALL of the wires. Nothing. Tester works 100%.

God I hate electrical gremlins.
I'm going to give the connections in the footwell plug a good cleaning out with a wire brush and carb cleaner. THat'll learn it

[Steve_D]

On my '97.
The Green wire at the footwell blower connector is ignition switched live from fuse 14.
The green wire at the module is ignition switched live from fuse 16.
The black wires from pins A1&A2 go to earth on the OS tunnel top.
The yellow wire connects module to blower.

All the other wires from the module are related to the ice warning circuit.

Steve

ETA no you do not need the ECU but you do need the ignition switched on.

Edited by Steve_D on Friday 10th February 00:02

[caduceus]

Thanks for yet another detailed and helpful post Steve. It really is appreciated.

Not been on the car today, but hopefully will get the garage door open at some point tomorrow.
I did check the one and only fuse for the heater/fan which should have been a 15 amp, but was 20. It was ok. Will have a look again tomorrow for the ones you have mentioned. Something is amiss. No power getting to the plug that goes into the control box/module
I do hope it's not a wire break somewhere that I have to hunt for...

[Cider Andy]

As others have suggested it's a good idea to check the motor itself isn't seized as they can have a tendency to. It's a Vauxhall unit. Some of the burnt connector problems at the speed control ECU are caused by a failing motor drawing an overcurrent.

[caduceus]

Cider Andy said:

As others have suggested it's a good idea to check the motor itself isn't seized as they can have a tendency to. It's a Vauxhall unit. Some of the burnt connector problems at the speed control ECU are caused by a failing motor drawing an overcurrent.

caduceus said:

I tested the connections with the current setup and nothing. So then I removed the 12 amp (glass) fuse and tried again and the motor whirred into life!

From an earlier reply.

I just don't have power at the white multi pin plug that goes into the heater fan control module/box. Just about to go into the garage now and check the other fuse Steve mentioned.

[Cider Andy]

caduceus said:

I tested the connections with the current setup and nothing. So then I removed the 12 amp (glass) fuse and tried again and the motor whirred into life!

Ah, sorry, I missed that!

I blame old age...

[caduceus]

Cider Andy said:

I blame old age...

Or cider

[Cider Andy]

caduceus said:

Or cider

Yeah, that helps....!

[caduceus]

Ok, bit of an update. I have now got power to the plug that goes into the heater control unit in the dash. But it's still not working. I have tried both orientations of plugging in the ribbon cable and also tested it's continuity.

Is there a way of testing the box? I have taken it apart and see no obvious signs of damage:





Connector looks ok. No burnt bits.

Any ideas chaps?

Thanks in advance
Cad

[Pink_Floyd]

I would check with a multimeter that the component labeled FUSE is OK. A meter should say 0 ohms.

[QBee]

The simplest way of testing the box is to borrow someone else's and see if that works.
I did have a spare a few months ago, but sold it to a geezer from London with a similar problem to you.
I loaned it to him to try, and when it solved his problem, sold it to him.

[rovermorris999]

I think thermal underwear would be a permanent fix

[blaze_away]

I replaced the whole lot (switch and control box) with this on my chim. 98 model sith the full variable speed control. The only small issue being the shaft length on the new rheostat switch being 5mm too short. So I have temporarily removed the plastic light diffuser. It works a treat.


http://www.ebay.co.uk/itm/331765507177

[QBee]

If you want one, it's worth calling Douglas Valley Breakers to see if they have one for sale. Their website is always out of date, you need to phone.
As it will be off a Chim they are dismantling, ask for the plug and cable too, then if the main plug is your issue you stand a chance of solving that.

[caduceus]

Thanks for the replies.

Chris, I'll give that a go today. I do have a 'clamp meter', which doe shave probes. I assume that'll work?

These are the only two gadgets I have for testing:




The one on the left I know how to use for testing live and continuity. But the clamp meter.... I have no idea what setting that dial should be on.

[Paulprior]

if you want to use the clamp meter to test the fuse just plug the leads into the 2 left hand sockets and select the 200 ohm range just before 9 o clock, if you touch the leads together you should read very close to zero and by the looks of it you will get a buzz sound for confirmation

[caduceus]

Paulprior said:

if you want to use the clamp meter to test the fuse just plug the leads into the 2 left hand sockets and select the 200 ohm range just before 9 o clock, if you touch the leads together you should read very close to zero and by the looks of it you will get a buzz sound for confirmation

Thanks for the helpful reply Paul.

I just tried that test. Touched both the probes together first, and there is a bleep. The figure starts high and rapidly goes down to 01.0 and stays there.
I tested across the fuse and there is nothing. No beep or movement on the display. But then it didn't do that on a couple of other diodes on that board. Or is it only going to work on a fuse?

Please excuse my ignorance in this subject. I haven't a clue when it comes to electronics like this.

Cad

[FoxTVR430]

caduceus said:

Thanks for the helpful reply Paul.

I just tried that test. Touched both the probes together first, and there is a bleep. The figure starts high and rapidly goes down to 01.0 and stays there.
I tested across the fuse and there is nothing. No beep or movement on the display. But then it didn't do that on a couple of other diodes on that board. Or is it only going to work on a fuse?

Please excuse my ignorance in this subject. I haven't a clue when it comes to electronics like this.

Cad

Sounds like your fuse has blown then if you have no "beep" and the display is showing a high value. e.g. >200 ohms.

P.S. Diodes only let current through one way, so if you swap the leads around on the diode you should hear a beep