Heater blower motor

There should be resistors at the back of the motor.
Yellow wire is high speed so would be best to confirm the motor runs. In later cars this is the only wire used as the speed control is done in a module in the dash.

If the air lock won't clear disconnect both pipe and run a garden hose to one of them. When you have a good steady flow (and worth flushing it in both directions for good measure) clamp of both ends so the pipes remain full then reconnect them where they belong.

Steve

No, I meant in the engine bay.
Just flushing the heater from the footwell will not clear air in the rest of the pipework.

Steve

See if you can find the connector in the footwell as described earlier in this thread and put fused battery voltage on it to see if it will run ok.
If you run it for a while it may free up.
If it runs ok you need to check the voltage supply to it.
Horrible job getting it out though so good luck.

I had a similar problem in my Cerb. The motor was pulling too much current and blew the power FET in the control box. Turned out the lower bearing on the motor was rusted up. £3.99 for a new bearing. Common skateboard truck bearings. NSK BEARING 608-2RS-C3 NSK

I read this thread with interest because my fan doesn't work either I have the later aluminium switches with the ribbon cables. The light to the switch does work however. I checked all the connections at the black box (heater control unit) - all absolutely fine with no signs of over overheated wiring, checked fuses 14 and 16 - all ok. Checked the connection on the left side passenger footwell (a few inches infront of the door and found this (all taped together with electrical tape

There's the 4 wires coming out of the footwell wall, connecting to only 2 wires in the other connectors. The two blue wires weren't connected to anything, and neither were the white and white/pink wires...

It isn't meant to be like this surely - or has Stevie Wonder been trying to fix the heater before? When I look in the passenger footwell and see the loose wiring, random relays on the end of said wiring, and a fusebox bolted to the wheel arch with one 13mm nut, a cold shiver runs down my spine...

Looks normal Tvr to me, actually very neat compared to some cars!
You should have ignition 12 volts on the green wire, the yellow wire then goes back to the controller to do all the control.
Only 2 wires are used with the later control.
Fuse 14 for the ignition 12 volts.

Jeremy Clarkson would say "not having a big enough hammer to hand".

The most valid comment.
Many before you have found signs of burning at pin B1 or even worse that end of the connector melted.
You may have to bypass that pin and wire direct into the box.

Steve
PS You would not expect to get an output from the box as this wire is on the negative side of the motor.

As I said before the green wire at the fan is +12V the yellow wire back to the control box is from the negative side of the fan so there should be no power at the box. However, whilst I'm quite familiar with electrics I'm not so competent with electronics which is what is happening in the box. Perhaps someone else can explain why you were getting some sort of reading from that wire.

On earlier cars the switch supplied power to the fan via 3 different wires 2 of which went through resistors at the fan to change the speed. Our later cars have the control box which just connects to the fan 'high speed' circuit and the box controls the speed using 'black magic' (electronics...probably a MOSFET or somesuch).

Steve

It’s simple to bypass the bad terminal. Even I managed it.

Or send the box away to Jodie at Python Racing to have it mended.
I assume he still does them.
Paul Smith did mine, but he certainly used to have a bit of a queue.