Heater fan help

[davidd]

Morning,

My griff 500 cabin heater fan is now permanently on.

Was fine 10 days or so ago, then it decided to turn it self on with the ignition. It was low speed, almost like it was just turning over. I could still press the switch to make it come on properly, control the speed.

A couple of days later and it is now just on full power as soon as the ignition is on.

I've checked the lower dash, all looks ok. If I disconnect the ribbon cable the fan still keeps going.
The connections into the control box look ok.
I can disconnect the plug in the passenger footwell and it stops, plugging in obviously restarts it.

Before all this I disconnected the battery a couple of times as I was checking for parasitic drain and adding a ctek charging cable, so i do wonder if I disturbed something somewhere.

Any ideas?

Many thanks

David

[davidd]

I've done a little more investigation.

If I unplug the big connector from the back of the black control unit (under the radio) the fan keeps going on full power.

I noticed that there are two lots of live and two lots of earth going into the connector....



It there another switched power on a relay I should be looking at?

Thanks

D

[Adrian@]

davidd said:

I've done a little more investigation.

If I unplug the big connector from the back of the black control unit (under the radio) the fan keeps going on full power.

I noticed that there are two lots of live and two lots of earth going into the connector....



It there another switched power on a relay I should be looking at?

Thanks

D

Can I suggest you open the controller, look on the back of the board for burnt out tracks.
IF this is case the motor is starting to fail and resistance is being feed back to the controller.

Again if this the case, get a soldering iron out ...you may need to create links of burnt out tracks/replace the plug/connections...start double checking earths and maybe replace the motor (strip and refresh). A@

[davidd]

Adrian@ said:

Can I suggest you open the controller, look on the back of the board for burnt out tracks.
IF this is case the motor is starting to fail and resistance is being feed back to the controller.

Again if this the case, get a soldering iron out ...you may need to create links of burnt out tracks/replace the plug/connections...start double checking earths and maybe replace the motor (strip and refresh). A@

Thanks, but why would it still run when the big connector at the back of the control unit is disconnected?

[Geoff-Griff500]

These can take so long to fix. Mine was on all the time so took it to my dealer who has all the equipment to do this in a fraction of the time.
It now works and even the lights come on to say it's working.
Sometimes tinkering around is great, electrics, nope, unless that's your expertise.

[davidd]

Geoff-Griff500 said:

These can take so long to fix. Mine was on all the time so took it to my dealer who has all the equipment to do this in a fraction of the time.
It now works and even the lights come on to say it's working.
Sometimes tinkering around is great, electrics, nope, unless that's your expertise.

This is a very fair point. I thought I might have disturbed something when putting a ctek connector on the battery which is why I started to look into it.
I do as Adrian suggested and try and get the box out this evening and see if there is anything obvious wrong with it. Then it will be beyond me.

The car had a new fan 2 years ago so I wonder if this issue is related (as per the previous post).

If I get stuck then it will be back to Mat Smith.

I have headlamp bulbs to do this weekend, fingers crossed that goes a little more smoothly.

[davidd]

Right I have taken the board out.

I’m not sure there is anything obviously wrong but I m no expert.
Any ideas? The wiring is tight in the car so hard to test in situ.

Edited by davidd on Thursday 30th October 18:11