w126 ccu

[E150GT]

Does anyone know if the CCU from an 88 W126 is compatible with the CCU in my '86
420sel? I have had some trouble with mine lately. In the morning it clicks a little when it is really cold outside. Some times when it is clicking, the heater will turn on full blast in short spurts of 2 seconds or so for a little bit and I can see the light turn on and off on the recirculation button. I believe once it was warmed up a bit, I can get it to work properly. When on heat, it does blow at the side vents like it should, but I can't remember if its supposed to blow warm air at the windshield also when its on max heat and on economy mode and not defrost. Mine does blow warm air at the windshield. I purchased an 88 w126 ccu at the junkyards as a spare in case this one goes out soon. I just dont want to pull out my ccu without having a proper replacement. Thanks for reading.