Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Loss of heater fan speed

Thanks Richard. Will work backwards like you suggest, and if its likely to be the PCB, will leave well alone.

Leroy,
photos of the PCB. I suggest you try the lights on off trick to see if that works. If you find it is the switch that is faulty not the PCB I have a spare off my old PCB
John

Thanks John. Did the trick with the lights and the other switches but made no difference. Any idea of where to look for the motor so I can check the connections? Had a quick look in the passenger footwell and could see anything.

I presume the motor is under the inlet cover just under the bonnet where the bulge in the plastic is. Sorry I have never looked

I looked under the gauze for there as that was my thought but didn't see the wires as described, just red ones.

Bit of an update. I've located the motor, and it indeed under the bonnet untop of the bulkhead like John suggested. I removed the gauze filter and 3wires come from the motor but without taking things apart, I can't see where they join the motor. These wires are black, red and orange. Tracing these wires to the drivers side, I find the orange one connects to a green and slate wire and the black to a black wire. The wires come from the loom. The red wire doesn't connect to anything and was cut shorter than the black and orange wires and taped up. I've separated the bullet connectors and bridged them with a bulb, firstly the orange and green/slate. When ignition on and the blower started at the high speed setting, the bulb lit, but the blowers didn't work. The same for the black wire, and the bulb lit. All reassembled, and the high speed setting worked, but not the low on.

Does this mean that the problem lies with at the motor end? I've given the wires to the motor a jiggle and nothing happens when it's on the low setting, so might be able to rule out a loose wire, or maybe not.

Thanks for posting the pic’s John. So it’s looking like there might be a single and dual speed board. With the second relay (next to the 12 pin connector) missing on the single speed configuration.

Leroy from your second picture it looks like if you were to take another pic maybe with a bit more light from the flash you might be able to just see if the relay is there or not? Or if you could lay on your back and poke around with a suitable bent plastic probe you might be able to feel if that second relay was in place? I believe some early Roadsters only had one speed....

I'll give that a go Rog. Yours and John's pics are useful to understand what's going on, and what I might have. I definitely had two speeds not so long ago, but as I don't use them often I can't pin point when it stopped working. As I'm clearly getting power towards the motor from the slow speed setting, would that mean all is good PCB/RELAY wise?

I have the same 4 relays as John has above.

So yes it’s looking like the motor then if you have power on the slow speed out. If it was mine I think that I would isolate the motor and power the motor independently from a battery first to be 100% sure (but only if you are confident of the connections!). Just maybe there could be some weird current limiting going on with the pcb that I would check first before replacing/repairing the motor.