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Hey new guy here to the bimmer world, as i stated in the title my ccu doesnt light up or do anything, ive checked the fuses and they're good. I also tried replacing the ccu itself with another one but it still did not power up or do anything. I've had the car for about a week, just wanted to see if maybe there is something else i could check or try that Im missing. Ive done everything ive seen in the diys so far, checked and replaced fuses, unplug and replug the wires behind the unit to try and reset, try to replace the unit itself, and even the blower motor cause i saw some people said it shut down after that failed. Just want to make sure i did all that i could before i take it to a shop and pay who knows how much any insight would be appreciated thanks
Apprentice w/#yrs. exp.
Try a generic diagnostic scan from AutoZone, not the best,
But at this point could be helpful. btw, what is a CCU?
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BMW Tech Expert
I had to sit there and think of all the acronyms in my head for a while..
I *think* it's an uncommon acronym for the climate control unit? Difficult to say because there's so little detail to the post.
Have you tried putting a multimeter in the correct places to test voltage, and where it drops?
-Abel
- E36 328is ~210-220whp: Lots of Mods.
- 2000 Z3: Many Mods.
- 2003 VW Jetta TDI Manual 47-50mpg
- 1999 S52 Estoril M Coupe
- 2014 328d Wagon, self-tuned, 270hp/430ft-lbs
- 2019 M2 Competition, self-tuned, 504whp
- 2016 Mini Cooper S
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I don't know the car but here is the pin out for the connectors if you need it. Looks like the power comes in on Pin 2 of the 'Natural' colored 6 pin connector. Should be a yellow/green striped wire. You have two ground wires (solid brown in color) within the 18 pin connector. As an old phone tech, I always start with power and ground on something like this as suggested above.
A11 Heating and A/C control module
Connector location views
Pin assignments at plug connector X608
Number X-pin, color Description X608 6-pin, natural Plug connector Heating and A/C control module X610 18-pin, natural Plug connector Heating and A/C control module X613 3-pin, natural Plug connector Heating and A/C control module X18341 6-pin, black Plug connector Heating and A/C control module
Pin assignments at plug connector X610
Pin Type Description / Signal type Connection /
Measuring notes1 E Signal Locator lighting Connector, instrument and locator lighting 2 E Voltage supply Terminal 15 Fuse F28 3 E Signal, rear window defogger Rear window defogger relay 4 E Signal Water valves Water valves 5 A Signal Auxiliary heater (DDE only) A8680 Fuse carrier, engine electronics 6 E Signal Auxiliary water pump (DDE only) Auxiliary water pump
Pin assignments at plug connector X613
Pin Type Description / Signal type Connection /
Measuring notes1 E Signal Solar sensor Solar sensor 2 A Pressure sensor signal, air conditioning system Pressure sensor, air conditioning system 3 Not used 4 Not used 5 Not used 6 Not used 7 A Supply, A/C pressure sensor Pressure sensor, air conditioning system 8 E/A K-bus signal Instrument cluster control module 9 E Voltage supply Terminal 30 Relay, A/C compressor 10 A Electronic ground, A/C pressure sensor Pressure sensor, air conditioning system 11 A AUC heater ground AUC sensor 12 Not used 13 M Ground Ground point 14 M Ground Ground point 15 E AUC sensor signal AUC sensor 16 A AUC sensor supply AUC sensor 17 E Signal Solar sensor Solar sensor 18 A AUC heating supply AUC sensor
Pin assignments at plug connector X18341
Pin Type Description / Signal type Connection /
Measuring notes1 A RHD: Ventilation flap motor Fresh air/recirculated air flap motor, right Fresh air/recirculated air flap motor, left Defroster flap motor Footwell flap motor 2 E Stage 2 Ventilation flap motor Fresh air/recirculated air flap motor, right Fresh air/recirculated air flap motor, left Defroster flap motor Footwell flap motor 3 E/A Stage 3 Ventilation flap motor Fresh air/recirculated air flap motor, right Fresh air/recirculated air flap motor, left Defroster flap motor Footwell flap motor
Pin Type Description / Signal type Connection /
Measuring notes1 Not used 2 A Voltage supply Blower Blower output stage 3 E Sensor ground, air conditioning system Evaporator temperature sensor 4 A Evaporator temperature sensor Evaporator temperature sensor 5 A Left heat exchanger temperature sensor Heat exchanger sensor 6 E Sensor ground, air conditioning system Heat exchanger sensor
Member
Climate control unit, how can a diagnostic scan help isn't that only for when my cel is in?Originally Posted by MIKYZZ4
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What do you mean by where it drops?
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Member
Ok thanks for your input, I will try checking this when I get a chance because the fuses are fine so it has to be a connector or wire itself somewhere.
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BMW Tech Expert
they are saying you need to figure out where the voltage is dropping - assuming your HVAC unit (CCU) is still not powering up.
if i'm reading this correctly you've already tried another head unit, yes?
which fuses did you check? more than one controls the HVAC - and, how did you check the fuses? did you use a test light and verify power/ground?
what happened before the HVAC stopped working? in other words, was it working fine and all of a sudden stopped working? has the final stage resistor been replaced?
just because your CEL/MIL is not on that doesn't mean there are not stored codes in the various systems within the car. its possible there is a code for the HVAC, but more than likely this is just a common power/ground issue. as was noted earlier, you need to verify power/ground - its missing somewhere.
Last edited by shadowpuck; 07-27-2017 at 12:05 PM.
'95 325iS - auto to manual swap done!
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