Heater blower motor
Discussion
My heater motor hasn't worked since I bought the car earlier this year, it's not a problem but I would like to fix it anyway, ,does anyone know how the circuit works?, I guess there is a fuse, relay and selector switch, but which ones are they?, also how do the various speeds operate?, I have a 95 model.
I have had every fault known to mankind on these, so here goes.
Most common fault is the heater control box wiring.
The box is under the dash top, roughly behind the controls, black and velcroed in place. The wiring that TVR used was not up to standard, and as the fans get stiff with age the excess current tends to melt the wiring at the connector. Find the box (It helpfully has "heater control box" printed on it) and pull the big connector off and examine it. One terminal tends to be burnt out. You can bypass this (there is a thread somewhere on PH), replace it, or send the box/conector to Paul Smith, the man who designed it and who now mends the faults he designed in for a fee. pselectronicsolutions.co.uk
The switch or the box itself can also be faulty. Same solution, send them to Paul Smith.
I also had a fault with the bullet connectors near the fan itself. On my 1999 car they were under the carpet on the left passenger footwell side wall, about 6 inches in front of the door frame.
The final fault I had was that the wiring overloaded at the back of the fuse box. An electrician friend (Cerb owner) spent a happy two hours on his knees finding that one. When he took the fuse box off the bulkhead in the footwell, the brown wire was hanging loose off the back of the box, where it had burnt through.
Most common fault is the heater control box wiring.
The box is under the dash top, roughly behind the controls, black and velcroed in place. The wiring that TVR used was not up to standard, and as the fans get stiff with age the excess current tends to melt the wiring at the connector. Find the box (It helpfully has "heater control box" printed on it) and pull the big connector off and examine it. One terminal tends to be burnt out. You can bypass this (there is a thread somewhere on PH), replace it, or send the box/conector to Paul Smith, the man who designed it and who now mends the faults he designed in for a fee. pselectronicsolutions.co.uk
The switch or the box itself can also be faulty. Same solution, send them to Paul Smith.
I also had a fault with the bullet connectors near the fan itself. On my 1999 car they were under the carpet on the left passenger footwell side wall, about 6 inches in front of the door frame.
The final fault I had was that the wiring overloaded at the back of the fuse box. An electrician friend (Cerb owner) spent a happy two hours on his knees finding that one. When he took the fuse box off the bulkhead in the footwell, the brown wire was hanging loose off the back of the box, where it had burnt through.
2OOM said:
Does the 99 car have the TVR switch? mines a 95 and it has a vauxhall cavalier/astra vintage switch( as in the pic), I've not had any reason to look into my blower so can't help with any diagnosis, but I've never noticed any boxes with ribbon cables under the dash cover ..
Mine has the aluminium switch with ribbon cable, but the problem cable is 8 wires....If you pull back the carpet on the outer passenger footwell there should be a connector with 4 heavy wires.
In later cars only the Yellow and Brown wires are used with the Brown wire being negative and going to the control module. The Yellow is direct from Fuse 14
On that basis I would surmise that on the earlier cars:-
Brown is negative.
Yellow is fast.
Grey and Blue will be medium and slow but I don't know which is which.
My first course of action would be to find and unplug that connection and apply direct battery voltage to Yellow and Brown and see if the fan runs. If it does then test medium and slow. If all working then the problem is the switch, wiring to and from the switch or fuses.
All wire colours mentioned are the wires on the motor side of the connector. The wire colours used by TVR from the other side of the connector are different (why am I not surprised).
Steve
In later cars only the Yellow and Brown wires are used with the Brown wire being negative and going to the control module. The Yellow is direct from Fuse 14
On that basis I would surmise that on the earlier cars:-
Brown is negative.
Yellow is fast.
Grey and Blue will be medium and slow but I don't know which is which.
My first course of action would be to find and unplug that connection and apply direct battery voltage to Yellow and Brown and see if the fan runs. If it does then test medium and slow. If all working then the problem is the switch, wiring to and from the switch or fuses.
All wire colours mentioned are the wires on the motor side of the connector. The wire colours used by TVR from the other side of the connector are different (why am I not surprised).
Steve
Paulprior said:
I guess i could also then just measure to see if i get voltage on the non motor side of the connector, any idea what this connector looks like, theres a lot of stuff in that area?
I think it may be a bullet style moulded connector. These would typically have 1 male and 3 female terminals. Probably in grey or black slightly rubber like plastic.Steve
QBee said:
Paulprior said:
I guess i could also then just measure to see if i get voltage on the non motor side of the connector, any idea what this connector looks like, theres a lot of stuff in that area?
There's not a lot else IIRCSteve
do you think him or his pussy can fix TVR electrics though?Steve D got it right with the electrics, thank you, i separated the connector and found the switch puts 12v to each pin in turn for speeds 1, 2 and 3, i then measured the motor side and had over 5m resistance from the earth pin to the other 3, i also reconnected the two halves and measured the voltage while connected, all ok, so basically my motor looks to be Kaput, where is it? the cable disappears into the left side of the passenger footwell?
Thanks
That sounds fun, i was hoping for cables or fuse problem, i will wait until the weather turns, took it out again today with the roof off as the weather was so good
While i was playing around in the footwell i checked the water pipes, apart from it looks like at least one of them has been leaking i noticed that with the engine hot and running only one pipe was hot, the other just warm, i guess thats not normal and that without the fan on they should be virtually the same temperature, i had the dial set to hot, any thoughts?, the car doesnt overheat when stationary but the temp does rise quite quickly if i come to a stop and the fans cut in after about 2 minutes.
While i was playing around in the footwell i checked the water pipes, apart from it looks like at least one of them has been leaking i noticed that with the engine hot and running only one pipe was hot, the other just warm, i guess thats not normal and that without the fan on they should be virtually the same temperature, i had the dial set to hot, any thoughts?, the car doesnt overheat when stationary but the temp does rise quite quickly if i come to a stop and the fans cut in after about 2 minutes.
^^^^^^ yes do this before ripping it out. If it has not turned for a long time it may just be stuck and need a little persuasion to spin. Use 2 good thick cables direct from the battery to the motor terminals. If the cables spark as you touch the battery terminals then a good chance the motor is salvageable. If no sparks then probably dead.
I will give it a go, but not very optimistic, the resistance from motor supply to earth is very high but resistance across the 3 speed options is only 2 or 3 ohms, does anyone know if there are 3 sets of windings or just a set of 3 resistors feeding a simple motor?, 3 resistors for the speeds would explain my readings, i looked at how to access it today, not looking good, theres so much of what looks like white silicon holding that cover in place, i will remove the battery tomorrow and have a better look.
I also looked at the flow valve to the heater matrix, it moves nicely so i guess there must be an air lock causing the return pipe to stay cool, i guess i need to rip it all out and have a look, is there any other way apart from removing the pipes and putting air through it to test for a blockage?
I also looked at the flow valve to the heater matrix, it moves nicely so i guess there must be an air lock causing the return pipe to stay cool, i guess i need to rip it all out and have a look, is there any other way apart from removing the pipes and putting air through it to test for a blockage?
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