Heater control troubleshooting

[SergSC]

Heater has a mind of its own these past few weeks.

It often doesnt work (go to hot) when turning the car On from cold, if I forgot to put the heater Off the previous night when putting the car to bed.

If I switch it off before turning the car off, then it almost always works properly when starting the car from cold the next morning, until the next time I turn the car Off/On while hot.
For example, if I drive the car from cold for 5 minutes with heater On, then turn off heater, turn off car, buy petrol, then back On, then it wont work again until the car goes completely cold again...

Sometimes a heater stepper error comes up, sometimes not.

Sometimes but increasingly rarely I can get it to work again If I fiddle the temp and fan speed controls.

Sometimes if its working on hot it switches itself to cold without me thouching any controls.

Any idea? Before I start replacing parts at random.

Cheers
S

[SergSC]

Thanks guys, I'll check all the connections. Hope its not the dash ecu, again, as its only just been.
Cheers

[SergSC]

Think I found the cause. The capacitors look swollen, like they are about to burst and shower the OH's legs with hot stuff. I guess they still work for a short amount time after starting the car from cold, explaining the symptoms.

I bought caps from maplins, 1000uf 63V 105c temp rating (more durable apparently), but I think they are a tad smaller than the standard?

Anyway, the plan was to take the module out and solder them on, but I cant see how its attached, any tips?
Then to relocate to glove box area as per the other thread, any more pointers re doing that?

Many thanks
S