Question:
Since I last emailed you I have rebuilt the compressor and the valve block. Jumpered at the ECU cable to raise the vehicle all the way up and lower all the way down. All works great. Plugged the ECU back in and the compressor fails to run longer than a few seconds. I jumpered it at the relay and it pumps the suspension up. There are no faults – yes I got the program to stop showing 253. It was a miswire on from the db9 plug and wire color code…. I guess not all manufactureres follow the color code guides.
Answer:
IF the compressor cycles on and off every 30 -60 seconds, then this is almost always a failure in the EAS Driver pack. The EAS driver pack is located directly under the EAS compressor. When it fails, all sorts of strange things begin to happen with the valve block and the EAS compressor. You might also check the EAS pressure valve. The thermal switch on the back side of the compressor can also be a source of failure. When the thermal switch fails, the compressor will cycle off but not come back on until a very lengthy period of time. The compressor may even fail to ever activate if the thermal sensor has failed completely. The thermal switch is located on the rear of the compressor housing, next to the motor brushes. Visual inspection is almost always useful first, as failure can also be because of a physical malfunction. The compressor motor armature can loose a bushing which can make physical contact with the thermal sensor. This can cause incorrect intermittent overtemp signals from the thermal sensor.