V8 Freak Posted October 27, 2016 Share Posted October 27, 2016 Hi, Wondering if someone can confirm the wiring on an EAS compressor... I'm planning to sort some on-board air and have had an EAS compressor fall into my lap.... It's got two thick wires and one thinner wire. (Not with me at present so cannot confirm the colours...) I've assumed one will be earth, one power live and the other a trigger / switch for an internal relay? If anyone can confirm or advise otherwise before I go anywhere near to connecting it up it would be great. Thanks in advance. Neil Quote Link to comment Share on other sites More sharing options...
David Sparkes Posted October 27, 2016 Share Posted October 27, 2016 I don't know what you are using your on-board air for, but the EAS compressor is good for operating an Air Suspension system, provided the system is otherwise in good order, with no gradual but continuous leakage from perished air bags. I'm not sure the EAS compressor is good for anything else, but, you have one for free so you might as well try it. The wiring: The thick black is the Earth. The thick other wire (Purple with Light Green tracer in the wiring loom) is the Power feed, from a relay contact supplied by a 30A fuse. The thin wire is more interesting. The colour in the loom is Black with a Purple tracer. There is an internal connection to the Earth lead, but this goes via a thermal switch, When all is normal the thin wire is at full earth, when the thermal switch operates (from overheating) the earth feed is disconnected. The thin wire is connected to the EAS ECU, when the earth disappears the ECU breaks the operate circuit for the relay, so the compressor stops. The trick part is that the thermal switch doesn't operate very often, but when it does there is a tendency for it to stick open, rather than reset when it cools down. The dealership mechanic will change the compressor, as he should do. There used to be a supplier of thermal switches, and a 'how to' guide covering the replacement, in the USA, but I don't know if they are available now. The 'home mechanic' fix is to make a small jumper wire installation in the multi-plug, connecting the thin wire to the Earth wire. Of course, this loses the thermal cut out protection, but for free, what do you expect? With your 'independent' installation you probably weren't thinking of a temperature monitor anyway, so ignore the thin wire, just control power to the non black wire via a suitable relay. Don't be surprised if this is an interim measure, the next step is a two cylinder heavy duty 12v tyre inflater, at probably £60+, and then it's more time and money creating a drive for an air con compressor. But having fun is all part of the game :-) Regards. Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 27, 2016 Share Posted October 27, 2016 I wouldn't bother trying to use it. It's just too small. The wiring info given by David is correct if you do want to try it though. Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted October 27, 2016 Author Share Posted October 27, 2016 I intend using a small receiver tank and it's only going to be for top ups and emergencies..... In the old 110 I had a system I bought from SteveG with single cylinder T-max type compressor, small ish tank under the vehicle and pressure switch etc. It worked fine and was simple. Thinking of similar with small tank in rear wheel arch and EAS compressor & pressure switch in front wing.... I think I'll note the "improvement" in the wiring and not worry about thermal cutout as I don't ever expect the compressor to be running for that long. Thanks for the great feedback as ever, very speedy... Neil Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 28, 2016 Share Posted October 28, 2016 The stock system in the P38 has a 10L tank, which took the standard compressor about 5 minutes to fill... It really is a system made for pressure, not flow. Totally unsuited for tyres. I've got the aircon compressor hooked up to it now, which works well. But I still drain the tank filling up tyres. Quote Link to comment Share on other sites More sharing options...
V8 Freak Posted October 30, 2016 Author Share Posted October 30, 2016 Mmmmm..... Maybe a re-think then... Quote Link to comment Share on other sites More sharing options...
rrdude Posted April 23, 2017 Share Posted April 23, 2017 Rebuild it and keep it as a spare. Get a unit designed to fill tyres etc :-) Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted May 1, 2017 Share Posted May 1, 2017 I had an ARB compressor for my lockers and that had the tyre inflater kit on it too. It worked well enough on the tyres I had. I'd say if the EAS pump was free then give it a go, the EAS system runs at 10 bar, far more than you need for tyres so I think you'll be surprised how effective it is. Quote Link to comment Share on other sites More sharing options...
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