Strange problems with my e39 Touring's HVAC (wife's car, so even more important to fix lol)
AC on
3 blue dots on center vent and full blue on rear vent
outside temp sensor appears accurate
both zones set to 60 or lowest temp
issue when AC is on:
DS vents come out ice cold
Passenger side vents blow heat or slightly cool
floor vents DS & pass side blow heat
rear vent is cold but not as cold as DS
I have replaced the heater control valve thinking it was stuck open on the passenger side only. Part appeared original. Marginal/slight improvement or placebo affect?
I have pulled HVAC computer from my e39 M5 and swapped it to the Touring. No change in functionality, still heat comes from floor vents and pass side comes out slightly cool but DS comes out ice cold
any thoughts? wifey is preggers again so between her + baby and our toddler it would be great to fix it for them for the last month or so of AC days
e39: Heat coming from some vents with AC on
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BJerolimic
- Posts: 747
- Joined: Wed Sep 15, 2004 2:24 pm
- Location: Glen Ridge, NJ . . . . . . '98 318ti - '01 M5 - '08 X5
e39: Heat coming from some vents with AC on
and gone but not forgotten:
'00 323Ci Steel Grey / Black Dinan & UUC & Schnitzer mods
'89 325iX Diamond Black / Black 4dr 5spd Dinan chip, Ireland exhaust, H&R+Koni
'01 525iTa
Woah - congrats on the upcoming addition!
Had something similar in my E46. Research pointed to the temp sensor in the console, as that seems to determine the temp output in the footwell.
For me, turns out it was the small mirror I had clipped to the vent to see the baby seat. It was diverting cold air to the sensor low in the console, which made it seem colder than it was in the footwell. Removed the mirror, problem solved (coincidence or not...).
Had something similar in my E46. Research pointed to the temp sensor in the console, as that seems to determine the temp output in the footwell.
For me, turns out it was the small mirror I had clipped to the vent to see the baby seat. It was diverting cold air to the sensor low in the console, which made it seem colder than it was in the footwell. Removed the mirror, problem solved (coincidence or not...).
It's also possible you have a refrigerant leak somewhere and are in need of a charge (after fixing the leak of course). The HVAC system diverts available cold air to the driver's side when its cooling capacity is reduced by low refrigerant.
(Been there, seen that, got the T-shirt from my E46. Your E39 is of the same vintage so it's worth checking.)
(Been there, seen that, got the T-shirt from my E46. Your E39 is of the same vintage so it's worth checking.)
2011 Azurite Black/Oyster Individual 335xi
2003 Black Sapphire/Natural Brown 330Ci
2022 San Remo Green/Oyster 430i
2003 Black Sapphire/Natural Brown 330Ci
2022 San Remo Green/Oyster 430i
There's quite a few temp sensors in the HVAC system on an E39. The one in the unit itself behind the fan is one. I believe there's a couple more throughout the dash, and if one goes, you'll have weird issues like this.
Paruse through an E39 forum or the M5forum, and you might find a similar case that'll point you in the same direction.
Low refrig is another possibility. But you should notice a continued reduced A/C capacity through time.
Paruse through an E39 forum or the M5forum, and you might find a similar case that'll point you in the same direction.
Low refrig is another possibility. But you should notice a continued reduced A/C capacity through time.