Hi,

I have an 07 Disco 3 and it has developed an intermittent fault with the compressor not coming on. It is holding air in the struts ok but on occasion it vents and drops to the bump stops. When it runs again it lifts slowly and the corresponding message shows on the dash. So I know the compressor works and assume that it is raising slowly because the system is empty. On most threads that I have seen the common solution is just to replace the compressor. However I don't want to replace it before I am sure there is not something else causing it to shut down. My Icarsoft shows that the compressor is getting 14v although it is not running until the warning light comes on then the power is cut. I have taken the compressor out and it is relatively clean. The desiccant in the dryer is a whiteish and tan colour and some of the granules have broken down but there is not a lot of power which could clog the system. Not sure if this is an issue. I was checking the continuity in the cables and found that the red and white wires from the plug on the sensor cable to the compressor body have no continuity. Its been a long day but this tells me the wires are broken right? Does anyone know what the red and white wires are for and why they both go from the screw to the compressor body? Perhaps earth wires.

 

If the desiccant has started to powder its quite likely it is migrating thru the pipes to the valve blocks, this can make the compressor run longer then overheat and cut out.

 

Thanks Lonerangie. Yes my next job it to check and overhaul the valve blocks. I just need to try and figure out why the compressor is running intermittently.

 

If there is ANY breakdown of the desiccant, then its already into the system. The Hitachi compressors can be rebuilt and when doing so the dryer is also refreshed. Certainly the AMK dryer can be refreshed and they probably make rebuild kits for the compressor itself also. I recommend at the minimum getting the dryer rebuilt then give some time before rebuilding the valve blocks (a week or two). You want any particles from the broken down desiccant to get through the system as best it can. Otherwise the remaining debris will just foul up the valve blocks, again.

As for the wires, not sure.