Sunroof won't slide and heater ..doesn't

[beckyrachel]

I took the heater blower out and cleaned up the bushes, it now runs fairly well.
However it doesn't run in the car - I'm seeing 11.9V at the positive wire, but only with respect to battery earth - the negative wire (even though it has a link to earth) isn't showing a 12V difference with the positive wire - Mad I know, but there it is.
I had the transistor unit out of it, I was seeing what I expected to see across the transistor, but something is wrong. Not had the turny dial PCB out yet to see how manky that is - the mod will be done and hopefully I'll at least get something out of it.

I cleaned up the radiator thermoswitch connections, I now have a working rad fan - although it seems fairly slow. Further investigation needed there I think.

Inside, it's been leaking. Looks like it was the aerial, someone had tried to prise it off.
I took it off, cleaned it all up, sealed it and stuck it back on. Fingers crossed!

Sunroof...
It now lifts up, although it's weak. I've cleaned and greased that part of the mechanism.
When I try to slide it, it lowers and slides back about 1/2 inch then stops. No amount of gentle movement of frame, glass or anything else can persuade it to move back more than that 1/2 inch. Any suggestions for next step?

Anyway - it's getting there - slowly.

[mat_fenwick]

The positive side to the motor remains at 12 V via fuse 2, but it's the earth that's controlled via the transistor and dial. You should see a good earth at terminal 2 on the transistor module plug, and also at terminal 2 (for the illumination) and 3 (control circuit) on the dial PCB. It seems common for the earth on terminal 3 to develop a high resistance, so the quick fix is to link it to the earth on 2 for the illumination.

[Vanny]

In terms of the sunroof, where is the sunroof blind? If its slid too far back into the head lining then the glass bit might well be jamming against it, and hence stopping after an inch.

[Defender110]

It seems common for the earth on terminal 3 to develop a high resistance, so the quick fix is to link it to the earth on 1 for the illumination.

I thought it was no.2 to no.3 the lamp earth (if counting from the right facing forward (3&4 if counting from the left)?

[mat_fenwick]

You're right, Kevan, thanks. I've edited my initial post now. I couldn't remember whether is was 2 or 4 for the illumination earth (numbered as the plug moulding) so I checked with Haynes which stated it was 1 Maybe I should trust my memory more!

[electrokid]

I cleaned up the radiator thermoswitch connections, I now have a working rad fan - although it seems fairly slow. Further investigation needed there I think.

If you follow the wiring from the thermoswitch to the fan, if it takes the same route as mine, you'll find it goes via a couple of connectors in the area of the nearside headlamp - these tend to corrode as much as the thermoswitch connections and could probably do with a clean.

[beckyrachel]

sunroof - AH - I'd forgotten about the sliding cover. I can't see one, so that suggests it's inside.

I'll trace back the rad fan wiring now I know there's connectors - ta

2 to 3 - gottit. I'll try earthing the fan directly to confirm sufficient feed current first.

Not feeling well, so nothing much done today.

Many thanks for the info!

[mat_fenwick]

The radiator fan may be wired via a two stage thermal switch and resistor. This limits the current flowing through the switch contacts when first starting up, and only comes on full speed if engine temperature continues to rise. I've not owned a petrol BX, but the Peugeot 205s we've owned with the same engine have that arrangement.