1987 735i electrical probs - pls help

[Rohan 0]

I have a 87 735i with some electrical problems.:

1 - Heaters seem to have a mind of their own - turning itself on and off as it likes and unable to switch off.

2 - Cruise control sometimes stops working during driving (not during use, but after braking and trying to turn it back on again)

3 - Dash lights sometimes fade in and out (not fully)

Could this be a computer problem???

Any help much appreciated

[Docile 64]

heater? or the fan blower??

if its the fan blower its probably the fan control unit. had the same thing on my cousins e46.. would just blow on high randomly and then turn itself off randomly.

[kiwi535 538]

heater not turning off can be the valves at the rh back of the engine bay,they can stick open letting hot water always circulate through heater.Sometime a few sharp raps on the valves can free them but they will stick again.This can also be the cause for "variable" operation

[Rohan 0]

heater? or the fan blower??

if its the fan blower its probably the fan control unit. had the same thing on my cousins e46.. would just blow on high randomly and then turn itself off randomly.

Hey thanks for your reply, unfortunately its both lol

[Docile 64]

Hey thanks for your reply, unfortunately its both lol

me and my cousin had to replace the control unit.. cant remember how much it was... but i think it was 200 bucks new

[BM WORLD 1258]

I have a 87 735i with some electrical problems.:

1 - Heaters seem to have a mind of their own - turning itself on and off as it likes and unable to switch off.

heater valves fail , replace with good 2nd hand unit , fan speed controllers (sword) fail, that will shut the whole system down if the fan stops

2 - Cruise control sometimes stops working during driving (not during use, but after braking and trying to turn it back on again)

check brake switch is not coming on

3 - Dash lights sometimes fade in and out (not fully)

maybe replace the dial that adjusts teh brightness they get a bit worn over time .

Could this be a computer problem???

Any help much appreciated

also check fusable link near positive battery terminal they fail too.

that will stop , wipers , windows , heater , radio etc from working