Fog Light & Blower Fan No Worky

[Tyre Tread]

I was just checking the car over ready for MOT on Tuesday and found the foglight doesn't work.

Also noted that the heater fan is also kaput and wonder if there's a common fuse or something.

Had a quick look at the fusebox but nothing obvious.

Before I insert myself into the footwell with a meter does anyone have any insight that might be helpful on which fuse or relays to check.

As usual the SH book is nigh on useless when it comes to electrical issues.

Thanks in Advance.

[Tyre Tread]

Well the foglight was a cable that was pushed off the switch when the radio went back in so that's solved.

Now the blower motor which can't be the cable as the LED around the switch is illuminating

[QBee]

It can be a number of things:

1. The heater control box connector can burn out - the box lies in the dash top straight behind the heater controls. It is labelled. The burnt out main feed can be bypassed.
2. The fan itself can wear out or stick - that one's a bigger job because the fan is in the outside wall of the passenger footwell and has to be cut out.
3. It can be a fuse blown.
4. It can be dodgy wiring connections in front of the passenger door, side wall, under the carpet.

I have had all of the above apart from the fuse.

[s p a c e m a n]

My blower motor committed suicide recently and popped the fuse, this made all of the dash lights and gauges die and put the battery light on. I can't be more help as I just had to work my way along the fuse board to find the blown one, but if yours is wired the same as mine it won't be the fuse otherwise you'd have loads of other dead stuff.

[Tyre Tread]

QBee said:

It can be a number of things:

1. The heater control box connector can burn out - the box lies in the dash top straight behind the heater controls. It is labelled. The burnt out main feed can be bypassed.
2. The fan itself can wear out or stick - that one's a bigger job because the fan is in the outside wall of the passenger footwell and has to be cut out.
3. It can be a fuse blown.
4. It can be dodgy wiring connections in front of the passenger door, side wall, under the carpet.

I have had all of the above apart from the fuse.

Thank you for the pointers:
1. Yes, I took the dash top off and found the box but I just checked the cables were secure. Presumably I'd need to open ti box and look for any evidence of something having overheated.
2.I'm just hoping its not that but will get the Dremel out as a last resort.
3. I checked the fuse as listed in the SH Bible but it's OK
4. Oh, I didn't know about those so will take a look later in the week.

I've thrown it all back together for now until it (hopefully) passes the MOT on Tuesday and then I'll dig a bit deeper

Thank you again for the advice.

[Tyre Tread]

s p a c e m a n said:

My blower motor committed suicide recently and popped the fuse, this made all of the dash lights and gauges die and put the battery light on. I can't be more help as I just had to work my way along the fuse board to find the blown one, but if yours is wired the same as mine it won't be the fuse otherwise you'd have loads of other dead stuff.

That gives me a little more room for optimism as everything else but the blower seems to be working.##I'm not sure why a simple heater fan needs to have such a complicated control system. Presumably because TVR?

[QBee]

Tyre Tread said:

QBee said:

It can be a number of things:

1. The heater control box connector can burn out - the box lies in the dash top straight behind the heater controls. It is labelled. The burnt out main feed can be bypassed.
2. The fan itself can wear out or stick - that one's a bigger job because the fan is in the outside wall of the passenger footwell and has to be cut out.
3. It can be a fuse blown.
4. It can be dodgy wiring connections in front of the passenger door, side wall, under the carpet.

I have had all of the above apart from the fuse.

Thank you for the pointers:
1. Yes, I took the dash top off and found the box but I just checked the cables were secure. Presumably I'd need to open ti box and look for any evidence of something having overheated.
2.I'm just hoping its not that but will get the Dremel out as a last resort.
3. I checked the fuse as listed in the SH Bible but it's OK
4. Oh, I didn't know about those so will take a look later in the week.

I've thrown it all back together for now until it (hopefully) passes the MOT on Tuesday and then I'll dig a bit deeper

Thank you again for the advice.

No need to look inside the box - pull the creamy white block connector off the box and have a look at the contacts in the block - it will be obvious if one has burnt out. As the fan starts to fail it draws higher current and the main power connection isn't man enough for the job.
I forgot to day that the control boxes themselves can die - bypass the box and see if you get your fan back. They can be refurbed by Python Racing near Colchester. Google will find the address and phone number.

[Tyre Tread]

QBee said:

Tyre Tread said:

QBee said:

It can be a number of things:

1. The heater control box connector can burn out - the box lies in the dash top straight behind the heater controls. It is labelled. The burnt out main feed can be bypassed.
2. The fan itself can wear out or stick - that one's a bigger job because the fan is in the outside wall of the passenger footwell and has to be cut out.
3. It can be a fuse blown.
4. It can be dodgy wiring connections in front of the passenger door, side wall, under the carpet.

I have had all of the above apart from the fuse.

Thank you for the pointers:
1. Yes, I took the dash top off and found the box but I just checked the cables were secure. Presumably I'd need to open ti box and look for any evidence of something having overheated.
2.I'm just hoping its not that but will get the Dremel out as a last resort.
3. I checked the fuse as listed in the SH Bible but it's OK
4. Oh, I didn't know about those so will take a look later in the week.

I've thrown it all back together for now until it (hopefully) passes the MOT on Tuesday and then I'll dig a bit deeper

Thank you again for the advice.

No need to look inside the box - pull the creamy white block connector off the box and have a look at the contacts in the block - it will be obvious if one has burnt out. As the fan starts to fail it draws higher current and the main power connection isn't man enough for the job.
I forgot to day that the control boxes themselves can die - bypass the box and see if you get your fan back. They can be refurbed by Python Racing near Colchester. Google will find the address and phone number.

Good info. Thanks.

Will check it out tomorrow PM or Weds and report back.

Fingers crossed.

[Tyre Tread]

And the winner is.....


Number 1.



Thanks to Anthony for the pointers and I've emailed Python for details of cost etc.

Regards

Alan

Edited by Tyre Tread on Tuesday 30th March 17:48

ETA. MOT Pass with one advisory - slight play in o/s upper ball joint. Ordered and should be here tomorrow

Edited by Tyre Tread on Tuesday 30th March 17:58

[QBee]

If you sent them that photo hopefully they will send you back the new white plug as well as refurbing your box.
The burnt out terminal is the main power lead, which you can bypass by taking a wire from before the plug directly to the circuit board.

I am a numpty with electrics, so must have been given the instructions on where to solder, I managed it at the second attempt and it worked.....for a while.
The instructions will be in a thread on here from about 2014, and may also mention where I stored my soldering iron afterwards, which would be useful to know as I need to mend something non-car related and cannot find it.....

[Tyre Tread]

Thanks Anthony.

I contacted Python and it's £80 + VAT for the box refurb and £12 + VAT for the plug which, once postage is added is looking at the thick end of £120

However, when I looked closely at the box the only part that overheated was the earth connection.

The Fan is running when I bypass the box so I soldered a wire direct to the board to bypass the pin on the plug and reconnected it with the PCB out of the metal box/heat sink.

It then ran for about 30 secs at full tilt and then cut out. After playing with my laser thermometer I see it's cutting out when the voltage reg (think that's what it is) gets hot at about 40 Deg.

I'm going to put it back in its heat sink box with new thermal paste and see if it runs OK.

Thanks for the advice and support


ETA: All back together and working

Edited by Tyre Tread on Thursday 1st April 21:43

Edited by Tyre Tread on Thursday 1st April 21:45

[Penelope Stopit]

Just a thought

Is the fan motor drawing too much current through the control unit?

Too much current often causes meltdown

Motor bearings/bushes wear or run out of lubricant and then wear

Could always connect an ammeter into the circuit and take a look

Yes I know you've probably already thought about the above but just in case you haven't

[Tyre Tread]

Penelope Stopit said:

Just a thought

Is the fan motor drawing too much current through the control unit?

Too much current often causes meltdown

Motor bearings/bushes wear or run out of lubricant and then wear

Could always connect an ammeter into the circuit and take a look

Yes I know you've probably already thought about the above but just in case you haven't

I sat with the fan running for 10 mins with my laser thermometer on it and with the heat sink fitted it registered no increase in temperature which I imagine it would if there was a high resistance.

I will probably put the meter on it before I reassemble although without knowing what normal values are it would be somewhat pointless

[Penelope Stopit]

Tyre Tread said:

I sat with the fan running for 10 mins with my laser thermometer on it and with the heat sink fitted it registered no increase in temperature which I imagine it would if there was a high resistance.

I will probably put the meter on it before I reassemble although without knowing what normal values are it would be somewhat pointless

Laser thermometer?????? Feck me, I spit on the end of my finger then touch the heat sink and roughly calculate the temperature going by the self inflicted pain, people like you don't understand how others get by

Agreed, the heat sink would have got hotter and hotter if the motor was tight or burnt

Jobs a goodun

[Tyre Tread]

Penelope Stopit said:

Laser thermometer?????? Feck me, I spit on the end of my finger then touch the heat sink and roughly calculate the temperature going by the self inflicted pain, people like you don't understand how others get by

Agreed, the heat sink would have got hotter and hotter if the motor was tight or burnt

Jobs a goodun

Not sure what you mean by the bold bit?????

I was given a laser thermometer by a friend a few years ago. They're (now) about £20 on Amazon.

I had one so I used it, as I wanted to see if the fan was cutting off based upon reaching a specific temperature which I figured would mean there was some sort of thermal protection built into the circuit.

I'm not great with electronics so was trying to be careful and methodical.

Anyway, hope this info might help someone else and once again thanks Qbee and S p a c e m a n for their help.

[Penelope Stopit]

Tyre Tread said:

Penelope Stopit said:

Laser thermometer?????? Feck me, I spit on the end of my finger then touch the heat sink and roughly calculate the temperature going by the self inflicted pain, people like you don't understand how others get by

Not sure what you mean by the bold bit?????