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Whilst at the moment I'am driving around having blown up the suspension manually, I do intend in a few weeks overhauling the valve block and getting the system back to standard. I've had problems with drivers some of which turned out to be connection issues, but it has led me to wondering what it actually does and how? Is it a simple signal booster?Could it be replaced with 6 single off the shelf units?
 

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The driver pack is the actual brains that runs the solenoids. The ECU under the seat takes the inputs from the height sensors, dash switch door open switches, hatch open switch and brake peddle and handle as well as speed and tells the driver pack to raise or lower each corner and that it is safe to do so. At least that is the simplified explanation I received with my first P38.

You don;t say what kind of "off the shelf units" you would replace it with, nor does that really seem plausible. A few folks have tried to redesign the driver pack. At last check someone was pretty close. Unfortunately projects like this spend a lot of time on the back shelf due to lack of time.
 

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To add a bit more, the ECU sends signals to the driver pack telling it which solenoids need to be opened and the driver pack then switches each solenoid using peak and hold signals at high power. Marty_NZ did try designing a more modern replacement and built a prototype using off the shelf MOSFETS but in testing found that it failed at high temperatures. It is the encapsulated block of electronics bolted to the side of the valve block. Most common problem isn't the pack itself but the connections between the pack and the solenoids in the multiway connector although some have found failed solder joints under the encapsulation.
 

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1995-2002 Range Rover P38A
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..as other mentioned..its a driver, drives valves inside valve block...valves are driven by pulse signal of 25ms roughly, with initial low state of 50ms, triggered by input signal of 10V(amplitude of pulse signal is 10V as well, if im not mistaken)..i did play with this thing before and managed to get it work, where output driver i have used high performance solid state relays driven by PIC24HJ128GP202-I/SO which was generating pulse signals based on ECU input ...it worked well but i never put it in to PCB form..
 

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it failed at high temperatures.
I have heard that the majority of failures are attributable to heat, so, with that in mind, would shifting the driver unit to under the seat with the ECU have any effect on temperatures?
Yes, there will be wiring changes needed, but that is relatively easy and a heck of a lot cheaper than new drivers.
 

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The point of the driver is to deal with high(er) current switching to the solenoids. In doing what you suggest you would introduce some resistance because of the longer leads from where the solenoids are located to under the seat. This could lead to inconsistent operation of the solenoids and some heat in the wiring.

To combat this you'd need to use heavier gauge cable which would (IMV) rapidly become unwieldy.

If you've had 'connection issues' with the current driver set it's entirely possible this may be the root cause of your problems because poor connections and high current can cause significant localised heat. Probably better to sort out the issues at the outset, ensuring good connections etc, rather than modifying. Personally I think the drivers are relatively reliable in their normal environment. If you felt heat was a real issue then you could just install a small fan to circulate some air - probably an old PC power supply fan, or chassis fan, would do.

PU.
 

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Several folks have installed fan with less than positive results. The flaw in that idea is that you are moving hot air from under the hood across the already warm contents of the EAS box. In order for the fan concept to work fresh air would need to be ducted in from under the fender or from behind a head light. Some form of filtration would be advisable so your aren't filling the box with dust.
 
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