Hi all, I'm new to the forums so please go easy on me. I've been going through the effort recently of getting my ac running on my Early Model 1987 325I Sedan, the car has an all original AC system and in the name of budget I'd like to get it running on it for now.
When I bought the car a few years ago the the pressures were good and AC worked great for about the first year... Eventually fuses started popping and I started losing blower motor speeds. Left it go for the past few years while the car was getting repainted and catching up on replacing old parts. Now I have the car ready for the road again and with summer coming up wanted to get it running again.
Yesterday I started with pulling the blower motor resistor and giving a repair by cleaning the metal strip that breaks the circuit. Checked the blower motor while I was in there and all seemed good and looks like its been replaced at some point in its lifetime. Put it back together and had my fan speeds back and working great! But still no AC light from the switch and the compressor clutch not engaged. After some more digging and ripping the dash apart I found the AC Slider PCB Shorted and the connector burnt to it. Removed the PCB completely and jumped the wires together and what do you know nice cold AC!
Not without its problems though... With AC max cold and blower motor on in any setting the fuse would only last for roughly 10 minutes. Did some talking with a friend and he hinted that the system could be freezing up and causing a the fuse to pop. Figured it was worth testing so popped a new fuse in and ran the AC at about a quarter turn off max and was perfect for about an hour of driving before I noticed that I wasn't blowing cold air anymore, but my AC switch light stayed on! So I figured maybe after a few years of no operation pressures may have dropped so just to verify that it wasn't anything else I went to jump the low pressure switch and still got nothing, process of elimination went to just the high pressure sensor and found the connector shorted, plastic was melted together so I had to cut it out and wire in new connectors, tested a jumper on both pressure sensors and still no clutch engagement... but my AC light is still on! I would assume this means I'm chasing a short between the AC Switch and the High Pressure Sensor (or possibly my AC clutch causing the short) and while looking at wiring diagrams for my car I did see a Evaporator Temperature Sensor and I'm hoping this is my culprit (And not a random shorted wire that will be impossible to find). I wont be able to look into it more until Wednesday so just wanted to post this here to get some more outside opinions or advice. So please pitch in! I'll give most things a shot.
Quick little note I need to test voltages yet and will have to see if I can find my multi-meter.
I also need to get my hands on a 12 volt battery to test the compressor clutch for operation.
Thanks for reading any advice would be appreciated!
When I bought the car a few years ago the the pressures were good and AC worked great for about the first year... Eventually fuses started popping and I started losing blower motor speeds. Left it go for the past few years while the car was getting repainted and catching up on replacing old parts. Now I have the car ready for the road again and with summer coming up wanted to get it running again.
Yesterday I started with pulling the blower motor resistor and giving a repair by cleaning the metal strip that breaks the circuit. Checked the blower motor while I was in there and all seemed good and looks like its been replaced at some point in its lifetime. Put it back together and had my fan speeds back and working great! But still no AC light from the switch and the compressor clutch not engaged. After some more digging and ripping the dash apart I found the AC Slider PCB Shorted and the connector burnt to it. Removed the PCB completely and jumped the wires together and what do you know nice cold AC!
Not without its problems though... With AC max cold and blower motor on in any setting the fuse would only last for roughly 10 minutes. Did some talking with a friend and he hinted that the system could be freezing up and causing a the fuse to pop. Figured it was worth testing so popped a new fuse in and ran the AC at about a quarter turn off max and was perfect for about an hour of driving before I noticed that I wasn't blowing cold air anymore, but my AC switch light stayed on! So I figured maybe after a few years of no operation pressures may have dropped so just to verify that it wasn't anything else I went to jump the low pressure switch and still got nothing, process of elimination went to just the high pressure sensor and found the connector shorted, plastic was melted together so I had to cut it out and wire in new connectors, tested a jumper on both pressure sensors and still no clutch engagement... but my AC light is still on! I would assume this means I'm chasing a short between the AC Switch and the High Pressure Sensor (or possibly my AC clutch causing the short) and while looking at wiring diagrams for my car I did see a Evaporator Temperature Sensor and I'm hoping this is my culprit (And not a random shorted wire that will be impossible to find). I wont be able to look into it more until Wednesday so just wanted to post this here to get some more outside opinions or advice. So please pitch in! I'll give most things a shot.
Quick little note I need to test voltages yet and will have to see if I can find my multi-meter.
I also need to get my hands on a 12 volt battery to test the compressor clutch for operation.
Thanks for reading any advice would be appreciated!
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