Anyway, having had the car ('92 JDM BB1) sat for little while the heater motor wasn't working at all. Managed to partially remove the motor and found it to be seized. I managed to free it off, but then it only worked on full speed.
A little bit of google-fu pointed me at the transistor on the top of the fan housing. Managed to get the transistor unit out without removing the dash by removing the glovebox then removing the NS tweeter unit, behind which you'll see two 10mm hex head bolts, remove these, they're used to hold up a bracket for some cable connectors that sit in front of the fan unit. Once they're out of the way it's possible (with my relatively small hands and long arms) to get at the two fixtures on top of the transistor unit.
Once the transistor was out started testing it, the transistor itself was fine, there is a thermal fuse hiding under the connector terminals, which I've replaced with something which should be suitable based on the transistor spec. And all now works, not that it's been tested for long periods of time.
Either way, due to minimum order quantities I have another 9 thermal fuses if anybody else is in need?
Joe.
