A8 D3 Suspension Solid State Relay Upgrade
 

Sounds more reliable that the mechanical ones...
http://www.agmpartscomponents.co.uk/...865-031-2323a/

I haven't swapped mine yet so looking for a higher-quality replacement and will report back when I am sure it's compaitble.


http://www.hella.com/microsite-elect...OE0-530320.jpg

FUNCTIONS AND FEATURES
Noiseless operation
Pulse width modulation possible (PWM)
Protection features including overload, reverse polarity and over current
No mechanical wear out / high switching cycles
Low power consumption
In development
TYPICAL APPLICATIONS

Used in hybrid /electric cars
Daytime running lights (DRL)
Vacuum pumps

Looks promising, i replaced mine a year ago. What's the load rating for these?

edit: the one in the link is 22 amp.

Interesting,

Not sure what state my relay is in, it may well be the original one which could mean I am running on borrowed time.

What is this relay?
What does it do?
What happens when it fails or failing?

The relay is what switches the power to run the suspension conpressor. Rumours abound on the line about the contacts fusing together making the compressor run continually till it burns out. It's tucked away behind the dash sonic it fails you can't get to it to pull it out quickly hence the idea to go solid state to prevent the issues mentioned

Be interested to see what is found for a replacement.

New OE part is 40A which is about as high as they go but the Hella solid state say 22A continuous (30A cycled) and 80A overload protection.
I might still try it but may be worth waiting for mkII versions (they say never buy the first of anything new).
On here,
http://www.amazon.com/HELLA-H4177300...9G3K2YXS7FZN3S
there is a reviewer who used two in parallel for a 40W PWM fan.

My other worry is that the suspension ecu may not see enough draw from the relay coil and blow a code like - compressor relay open circuit or short to ground.

was this tried?

Important note.
According to the Amazon data, though this solid state relay has the same physical layout as the OEM the actual internal wiring is different. It will not work as a direct swap.
First thoughts are that a jumper cable made up from an old relay base to a new relay socket (adjusting the connections) would do, but then that would be an idea (pin to pin connection) to enable repositioning the original relay to an accessible position.
As far as I am aware mine is still the original.

Does the orginal relay burn out due to........

1 the compressor motor windings getting a high resistance

2 small air leaks on system so compressor has to 'top up ' more

or it should have had a heavier relay in the first place