Heater blower goosed?

[caduceus]

My heater blower has not worked since I've owned the car. So now it's in a state of undress, I thought I'd try and source the problem. Although after doing a search I only found one thread of this problem and taking the blower out sounds about as enjoyable as setting fire to ones pubes.

I remember that I've checked the fuse, but that's it. I've checked the button/switch with a 'combi check' tester thingy bob, and the two left terminals make it beep And with my leccy knowledge (which you could document on the head of a fleas penis) I can deduce that the switch works. I think
So check the plug that's in the dash that feeds it and see if power is going there. If it is, the fan is fubar. Right?

Thanks in advance for any help
Cad

[caduceus]

rovermorris999 said:

Can you put 12v directly to the motor to test it?

Hi Nick. No. Not unless I remove it, and by all accounts that is not a nice job And my sense of adventure and humour is running out on this project :|

[caduceus]

Sorry for the tardy reply chaps. Thanks very much for your replies. Steve, that is handy knowing the wire colours. Will be trying this all out this morning. If it gets working I owe you all a beer at the next TVR meet
Yes, it IS the later type Chim that has the ribbon cable and ally switches.

Fingers crossed.

[caduceus]

Well I think I've found the plug a few have mentioned, behind the carpet in the passenger foot well. But the colours don't match up. Only a yellow and a green are on one end, the other being all the wires. Although I don't see a brown there either



I have tried shoving that red wire (which has a 12amp in line fuse in the holder) in both the yellow and the green, and nothing.I assume it makes no difference whether you unplug it or not? As the temporary + feed gets stuck in to the wire in the plug anyway.

[caduceus]

I unplugged it anyway, still nothing. Are the indicators supposed to work when you test it? (the indicator stalk was on at the time)

[caduceus]

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?

[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

[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...

[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.

[caduceus]

Cider Andy said:

I blame old age...

Or cider

[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

[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.

[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

[caduceus]

FoxTVR430 said:

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

When testing the fuse on the PCB, there is no beep OR any reading. There is no reading of 200 ohms.
I assume this means the fuse is toast?

Thanks for the tip re the leads. I tried both ways, still no dice.

[caduceus]

Paulprior said:

If the fuse is blown you need to check the motor doesn't have a short to earth.

Thanks for the reply as usual, very helpful. Not sure what a 'short to earth' is though...

[caduceus]

Thanks again for the info Paul. Will give that a try.

[caduceus]

Steve_D said:

I've had a quick look back through the posts but cant see anywhere you confirming that blower motor and all the wires to it are working.

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!

Steve_D said:

To do this you need the fan plugged in at the footwell, the ignition switched on, all the fuses in place and the connector unplugged from the module. Then short to earth pin B1 (Yellow wire) of the module connector.
If the fan works then you know the problem is in the module or its positive and negative supplies.

That's very helpful. thanks Steve. Didn't have time to bugger about with the car today, but will hopefully give this all a try out tomorrow.
So connect the yellow wire to an earth somewhere...? Sorry for being an electrospastic.

[caduceus]

Ok, I just tried the yellow wire port that is in the plug that goes to the module, to earth, and the blower worked!

So I guess it must be the fuse in the module. I have ordered a couple of 500 milliamp fast blow fuses for the PCB this week. They should be with me today. So just the delicate job of soldering a new one on top of the old to see if it all works.

I didn't bother with the B1 to B2 Steve, because I wasn't sure if you meant loop/connect them together, or each one separately to the yellow, or each one separately to earth

[caduceus]

Excellent. Thanks Steve. Most helpful.