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Discussion Starter #1
Hi Guys sorry for the delay in updating you. weather etc and getting home in daylights been the problem.
So I have now remade all the grounding points on the front of the car, from the foot wells forward.All referenced using RAVE info. Ive opened the loom in the EAS block through bulkhead area and proved to myself that the ground splices are good.
I have spliced into the diaphragm ground and also the valve block driver ground wires(before the driver wires connect to the EAS ECu connector C152.
The pump will now operate and fill the air tank from empty to full in approx 7 mins.
None of the other solenoids will energise when the ECU instructs them to. I have proved continuity through all cable and connectors to the valve driver and logged power at the driver output pins in C139 . I.e 12v were expected. BUT none of the "hit and drop pins produce any voltage reading.

My question is - should the hit and drop pins show any voltage during demand (if so how much) or are they working as grounds?
This is a brand new driver pack from island 4x4 as I stated earlier in the post. Hooking up the old one produces the same results. All 6 solenoids (excluding the diaphragm) do not respond.

To hopefully help you help me ,Ive tested all solenoids with 12v and a ground and they will all click the valves open.
I said I wont give up but wow.
 

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Don't know if this will help, or I'm showing you something you already know!
eas driver.JPG
 

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Discussion Starter #3
Thanks orangebean. I have seen this before. I am trying to establish if I should have 12v input to a solenoid which drops down I believe to a holding voltage on one wire and ground on the other wire.

Or does the output from the solenoid report that the coils energised to the driver pack.

in short one wires power in ,what does the other do? I dont want to spend another 150 + on a second new driver pack unless im sure its at fault.

many thanks
 

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LEGACY VENDOR
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It works on PWM - Pulse Width Modulation, as it all says in the blurb above the diagram that OB posted up.

You have a 12v power wire to each solenoid, and the other side is connected to the driver pack (probably with a flyback diode across it to the +ve feed). The driver pack actually controls it on the ground wire.

The voltage going to the solenoid doesn't drop, but the current to it. The 'hit and drop' works by providing solid ground to complete the circuit, with an inrush current of about 3A (on a 4ohm coil), which is the 'hit' to pull the solenoid valve in.
The 'Drop' the then the driver pack going into PWM mode - where instead of providing constant ground, it gives 'pulses' of ground connection every x milliseconds, which then means the current drops off that the solenoid is drawing as it needs less current to keep the solenoid valve open, than it does to pull it in to start with.

The EAS ECU provides a constant +12V control signal to the driver pack to activate the particular solenoid. The driver pack then grounds the other side of the solenoid coil to pull the valve, and then pulses the ground to keep it open (and thus reducing power draw and not burning the solenoid coil out).

So you will see permanent 12V to the solenoid coils, as the final drive of the system is 'Low Side' controlled - IE the ground is being switched, rather than the 12V.

If you were measuring the ground, then in theory you should see an average voltage with the solenoid being held in - but it might not read much less than standard, as the driver pack is pulsing in PWM mode very quickly - I *think* about 24khz - or 24000 times a second. and the initial 'hit' or full DC to the solenoid is for about 50ms.
 

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Discussion Starter #5
Can I just say. What an absolutely superb answer.
I have searched and searched for an explanation to my question. Thank you so much for taking the time really explain clearly. Very much appreciated.
Armed with the info I feel I can finally fix the problem. Highest regards John
 

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Hi John,

No problem - glad I could help!

If you have a new driver pack, then the first thing to check would be to unplug the driver pack connectors and check the control wires from the EAS ECU are getting 12V when they are supposed to be driven.
If you get 12V there, then the ECU is trying to tell the valve block to do something!

Something else you can try actually... which might be more beneficial...

With the valve block and driver pack all connected up, disconnect the EAS ECU and then try using a jumper wire to open each solenoid directly from the EAS ECU plug.

There is some information on the home page site here:
http://www.rangerovers.net/repairdetails/airsuspension/suspump.html#jumpers

In the first column of the table gives you what pin each corner + inlet/exhaust is connected to. Pin 1 as it mentions is 12V.

If you jumper between these pins, then it will be the same as if the EAS ECU is outputting to the driver pack to control the system. If you get a 'click' from each corner and inlet/exhaust then you know the wiring/driver pack/valve block are all good and for some reason the issue is with the EAS ECU

If you don't get anything from the driver pack/valves, then you know there is definitely an issue in the vehicle/wiring/EAS box...

Obviously it might be worth checking Pin 1 for 12V aswell... just in case that is missing and causing the problem (though I'd expect nothing on the EAS to work if this were the case!

Marty
 

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Discussion Starter #7
Hi Marty
At last the old banger is back on the road. Armed with your description of the valve drivers operation I duly checked the outputs from the driver to the valve solenoids.
Found power to them as required. The fault lay with the driver packs control of the "ground wire" or wire as you described from the solenoid river pack. I bought another driver pack plugged it in and all works as it should.

I hope I can get a refund from the suppliers for what turned out to be a faulty NEW part straight out of the box.

God forbid anybody goes through the same aggro as me but when you've checked all connectors , grounds , cable continuity and relays etc then as Sherlock Holmes said "when you have discounted the probable it then must be the improbable".

Thanks for all on the forum for the help full posts John
 
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