Hi. We are parting out a W126 and sold a climate control unit to a gentleman on eBay. It was functioning when we removed it. The customer installed it and still has no blower, no AC clutch engaging, no AC, no heat, it's just dead. He said he checked the fuse and it's OK too.
Anyone have any suggestions?
I just redid my air in aW126... there are many items that could stop the AC... Sensor in the compressor, high and low pressure sensors, Klima/Kickdown relay. Sounds like he has many problems to solve.
Regards, NRK
Keyser Soze wrote:
His problem wasn't the control to begin with. He will have to begin trouble-shooting the system and assume the control module is okay. I would first tell him to check and make sure there is enough refrigerant in the system. If this is too low the AC clutch will not engage. To check and see if this is the problem have him pull the electrical connector on the pressure switch (usually located near the drier tank) and put a jumper between the two terminals on the plug, not the switch. If the system doesn't have enough pressure to close the pressure switch, the AC compressor will not engage. If the clutch engages with the jumper wire in place then the system is simply low on refrigerant. I'm guessing this is the problem. When recharging the system, assuming it is simply low and not busted open somewhere, he will need to leave the jumper wire in place until the low side pressure comes up to at least 32 psi. I like to recharge the system by viewing the sight glass (normally near the drier) and continue introducing refrigerant until the bubbles completely disappear. Some techs like to use pressure alone as an indicator of a full system but bubbles always seem to reduce the system's ability to cool properly. Good luck.
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