heating and a/c problem.

Hi. Ive just got an e32 735 and the heater and aircon don't seem to be working properly .ac pump wont go at all and i keep getting hot air from the vents I suspect a control problem any clues?? [I have a parts car for spares]

does the compressor engage when u turn on the a/c? If not, jump out the low presure switch, if it engages it is low on freon.

First check is the pressure on the AC system and be aware that the Stepper Motors are notorious in these cars for failing or having the mount fail and jamming the vent flaps. go to http//:bmwe32.masscom.net/ for a look at Johan and Sean's site and the stepper motors and vent flap fix.

Thanks guys, I've started to look through to find te problemand I think I have 2 faults . one the a/c is'nt going [I willdeal with this next] First the heater vavle is not turning off ,I've striped it and tested it and it is fine as you probably know it needs 12v to turn off and here is where the problem starts. putting a multimeter on the feed plug connections I get only 5 or6 volts and using a very low wattage test lamp [12v] it glows very dimly but useing a larger 20 watt test lamp it won't glow at all ,with the small lamp I can get it to turn on and off with the heater controls .I need to find the sorce of this power[I thought it would be a relay but pulled them out 1 by1 and the lamp would not go out but i found the one that controls the heater pump] Unfortunatly I dont have a manual or a wiring diagram [any web sights I can get one from??????] Any clues guys???? [Manuals are hard to come by down here in New Zealand because there about $350 half a weeks wages!]

Thanks guys, I've started to look through to find te problemand I think I have 2 faults . one the a/c is'nt going [I willdeal with this next] First the heater vavle is not turning off ,I've striped it and tested it and it is fine as you probably know it needs 12v to turn off and here is where the problem starts. putting a multimeter on the feed plug connections I get only 5 or6 volts and using a very low wattage test lamp [12v] it glows very dimly but useing a larger 20 watt test lamp it won't glow at all ,with the small lamp I can get it to turn on and off with the heater controls .I need to find the sorce of this power[I thought it would be a relay but pulled them out 1 by1 and the lamp would not go out but i found the one that controls the heater pump] Unfortunatly I dont have a manual or a wiring diagram [any web sights I can get one from??????] Any clues guys???? [Manuals are hard to come by down here in New Zealand because there about $350 half a weeks wages!]

P.S I can't get into sean & johans site. any clues???.

Hi Guys - I have just found if I put a seperate 12volt feed into the heater solenoid, it works. So the lack of volt problem appears to be in the 12volt feed side, not the negative switching control side. Don't know where the feed comes from (due to no wiring diagram), so if I can't find the actual problem, I may just put a fused jumper lead straight to heater solenoids and try this. I have a good 12volt supply at fuse 20 which seems to be the one feeding this system. Any clues?


Thanks

Ian

Try going to roadfly.com and telling them what you have told us. There are a great number of BMW owners and technicians at that site. Also, there was a New Zealander that posted and had a website (can't remember his name) but ask, he owned and maintained a 735i.

Hi I've had some luck!! heater is working now, I'm pretty sure it was the 3 pin plug into the main heater control panel I have to say BMW electical wires and plugs are absolute rubbish as the have gone all hard and brittle and the female connectors inside of the seem to lose there tension [sofar it seems to be onle the plastic and inslation under the bonnet, must be the heat?] . I managed to get onto Johahs website AMAZING!!! I downloaded a wiring diagram which is very well set out [although some colours are incorrect maybe because it's for a 91 andmine is a 89??] now to find the air con problem. Thanks.