heater issue

heater issue

Author
Discussion

Andy70

Original Poster:

1,301 posts

166 months

Saturday 2nd November
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Hi all, I have a connection issue with my heater motor/blower, it stopped working and coincidentally my radio stopped as well, the next day they both started working again, well for 1 trip any way, the bizarre thing is the heater stopped again and continues not to work, but the radio continued to work, bummer, why couldn't it be the other way around, question is, is there a common connection or earth that these share? or any common issue where a bad wit of wiring could be? (please tell me I don't have to strip half the dash or anything to get to it! lol

Belle427

9,738 posts

240 months

Sunday 3rd November
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May just be coincidence as if it were a ground issue I'd expect other things to play up too.
They probably ground at the famous transmission tunnel bolt which can become loose and is always worth checking out.
Concentrate on the radio as it's easier to get at, you could add a temporary ground to battery to test it out.
Later cars had an electronic control box for the heater fan under the dash, the pins do burn out on them so it's worth inspecting it.

Andy70

Original Poster:

1,301 posts

166 months

Sunday 3rd November
quotequote all
Belle427 said:
May just be coincidence as if it were a ground issue I'd expect other things to play up too.
They probably ground at the famous transmission tunnel bolt which can become loose and is always worth checking out.
Concentrate on the radio as it's easier to get at, you could add a temporary ground to battery to test it out.
Later cars had an electronic control box for the heater fan under the dash, the pins do burn out on them so it's worth inspecting it.
Believe it or not the radio has behaved itself ever since, but not the all important heater, the car sorry is a 2000 plate 4L, So where should I check? sorry my technical knowledge is non existent


Oh just to help others out if anyone is remotely interested, from previous issues... I changed the gearbox oil, filled with Mobil ATF 220 is it? that seemed to cure my sticky gearshift issue...... I changed the stepper motor (for an OE one), that largely cured my high tick over issue after a few teething troubles setting base idle, I think there is still a small vacuum leak as the rev counter hunts just a tad, I get so little chance to play ow as evenings are drawing in so jobs will have to wait

Belle427

9,738 posts

240 months

Sunday 3rd November
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BritishTvr450

413 posts

6 months

Sunday 3rd November
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There is a block connector tucked up behind the glued on carpet just in front of the passenger door in the footwell.
From memory it should have both a green and slightly larger yellow wire and possibly black wire going into it.
This block connector carries wires from the heater control unit through the connector and into the heater box and activates the fan.
You could pull this apart and put direct feeds from the battery to the connector going to heater box to check the fan is working.

If that proves successful you then probably need to check the heater control unit connections by removing the dash and finding that unit and pulling the large block connector off.
As Belle427 has pointed out the contacts in that unit can burn out causing the fan not to receive power. That block connector contains the wires mentioned above that firstly go into the control box then back out to your block connector in the passenger footwell and then onto fan box.
Basically power goes into the control box then via your heater knob where you set how fast the fan spins then back out of control box to your fan.

Control box unit


Control box block connection


As you can see there is evidence of heat related burn out.
Sometimes you can clean up the connections and get control box working but just as likely you will need to replace control box itself.
First job would be to check your fan motor is working by putting power to it via the block connector in footwell area.
If your not technically comfortable then let your local Tvr centre or auto electrician who has Tvr experience do the checks as you will have to move quite a bit of wiring under the dash to get access to the control unit.


BritishTvr450

413 posts

6 months

Sunday 3rd November
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Belle427 said:
I wish I’d seen this post before writing all that drivel thumbup

Andy70

Original Poster:

1,301 posts

166 months

Sunday 3rd November
quotequote all
hey thanks for that, lots for me to check, probably take me weeks to get around to it as its dark i the evenings now, electrics baffle me, but I'll try and give some feedback if I get chance to do anything..... hopefully, just looking where the nuts are you get the dash off if I need to, but I'm sure the motor is working as like I said, it started working better than it ever did before in fact then stopped again

Edited by Andy70 on Sunday 3rd November 20:42

BritishTvr450

413 posts

6 months

Sunday 3rd November
quotequote all
Andy70 said:
hey thanks for that, lots for me to check, probably take me weeks to get around to it as its dark i the evenings now, electrics baffle me, but I'll try and give some feedback if I get chance to do anything..... hopefully, just looking where the nuts are you get the dash off if I need to, but I'm sure the motor is working as like I said, it started working better than it ever did before in fact then stopped again

Edited by Andy70 on Sunday 3rd November 20:42

In that case first check heater knob is connected to the control unit by a ribbon type connector cable so check that’s connected properly at both the knob and unit before moving on to the control unit main connector block.
Both the MIL light and ice warning light are wired through the main connector block into the control box which are the other wires you’ll find in that connector block. I think it just uses the power source into the control unit to power them.

Edited by BritishTvr450 on Sunday 3rd November 21:06

Andy70

Original Poster:

1,301 posts

166 months

Sunday 3rd November
quotequote all
BritishTvr450 said:
Andy70 said:
hey thanks for that, lots for me to check, probably take me weeks to get around to it as its dark i the evenings now, electrics baffle me, but I'll try and give some feedback if I get chance to do anything..... hopefully, just looking where the nuts are you get the dash off if I need to, but I'm sure the motor is working as like I said, it started working better than it ever did before in fact then stopped again

Edited by Andy70 on Sunday 3rd November 20:42

In that case first check heater knob is connected to the control unit by a ribbon type connector cable so check that’s connected properly at both the knob and unit before moving on to the control unit main connector block.
Both the MIL light and ice warning light are wired through the main connector block into the control box which are the other wires you’ll find in that connector block. I think it just uses the power source into the control unit to power them.

Edited by BritishTvr450 on Sunday 3rd November 21:06
great, will do thanks

PabloGee

471 posts

27 months

Sunday 3rd November
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BritishTvr450 said:

…Both the MIL light and ice warning light are wired through the main connector block…

Edited by BritishTvr450 on Sunday 3rd November 21:06
Reading out of interest, and now have a question / did TVR install an ice warning light from the early days?
I have never seen anything of the sort in my mk1.

To be fair, if it’s icy, the TVR is staying put…

Belle427

9,738 posts

240 months

Monday 4th November
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Supposedly fitted to later cars only but who knows with TVR. The thermistor is normally found under the centre of the radiator somewhere and can fail due to the location.

BritishTvr450

413 posts

6 months

Monday 4th November
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PabloGee said:
Reading out of interest, and now have a question / did TVR install an ice warning light from the early days?
I have never seen anything of the sort in my mk1.

To be fair, if it’s icy, the TVR is staying put…
I think it came in from the Mk2 cars or maybe when they started using the Cerbera digital clocks and dials.
It was quite useful as it would come on at 3 degrees so fore warning you of impending peril biggrin