126 CCU issues
 

Hi All,

My 1987 560 sel is having issues with the climate control unit. When it's cold out (I mean Canada winter cold) the blower motor will not start up when I first start the vehicle. After letting it warm up for a bit (5-10 mins) I shut the vehicle off and restart and the blower will work. If it is especially cold, the motor will come on intermittently with a clicking sound coming from behind the control panel. Seems like an electrical problem as the motor blows strong when it finally does start up. On my way to work today (-25 C) it decided to turn on when I got to the parking lot as a slap in the face.

Any thoughts would be appreciated.

First check the blower fuse located in an auxiliary fuse holder ahead of the brake fluid reservoir. It is a 30 amp strip fuse that can crack and open intermittently. Touch it in the center and see if a crack opens up.
Also check the lower current fuse(s) in the fuse box that feed the climate control system. The ones with the silver coloured element can develop corrosion at the contact points. Spin them for a temporary fix but replacing with the copper/brass coloured ones is best.
Next time it acts up, wiggle the ignition switch. There is a terminal coming off the switch that powers the blower. It can become intermittent at the worst possible time. Mine acted up at -30 degrees C.
The push button assembly is also a possibility. Solder joint cracks develop that can cause a wide variety of problems.

On a 126, if the system is in heat mode, the fan won't come on until the engine gets to around 60c. You could have a thermostat problem. If you press the defrost button, the fan should come on even if the engine is cold.

I can't say what happens at -25c. If it gets to 0c where I live, I stay in the house.

PaulM