Power steering fault finding

[Paulytrewq]

Hi, my MK2 power steering has stopped working I’ve checked the forums for possible causes so first checked fuse 35 and retrieved it from behind the pedal box 🙄 all ok (although fitted with a 20A instead of 10)
Found the power steering pump relay (I think - in the engine bay between the engine and header tanks) stripped it and tested it - all working fine off a 12V supply. Checked the output to the relay from the car by putting a meter across the pins 1&2 in the plug on the car, turning on ignition and then de-activating the immobiliser I get a 12V feed for a second and then it stops again in time with the fuel pump priming. I can repeat that with the relay in and see the relay briefly activate.
Once started I have a constant feed to the relay but when putting the relay back in I have no power steering.
Finally with the ignition off I have 12V to pin 3 which is the feed to the switched side of the relay, if I manually switch the relay by pushing the contractor over the feed to pin 3 drops to 0V…
Checking pin 5 (the output to the pump) in the connector on the car it is virtually shorted to earth (4.5ohms)
I’m thinking that probably means the pump itself is shorted but then again not sure what resistance I should get across a healthy pump winding.
Any help gratefully received.
Thanks, Paul

[glow worm]

I had lots of trouble with the Grey Citroen relay, after replacing 2 or 3 times, had it completely replaced it with a higher rated one and moved to inside the car out of the engine bay.

[Polly Grigora]

4.5ohms meaning a current draw of less than 3 Amps doesn't seem anywhere near high enough for an EPS pump

Comes across as the supply to the relay is breaking down under pump load

[Paulytrewq]

Polly Grigora said:

4.5ohms meaning a current draw of less than 3 Amps doesn't seem anywhere near high enough for an EPS pump

Comes across as the supply to the relay is breaking down under pump load

Good point - my meter is reading 1.5 ohms on relatively short runs so likely a bit out!

[Paulytrewq]

glow worm said:

I had lots of trouble with the Grey Citroen relay, after replacing 2 or 3 times, had it completely replaced it with a higher rated one and moved to inside the car out of the engine bay.

Moving inside is a good plan once I’ve worked out why it’s not working 👍

[Paulytrewq]

Think I’ve found the source of the problem - thanks all

[Paulytrewq]

Now just need to find a replacement fuse and holder

[Polly Grigora]

Nice

Mega are better

https://www.autoelectricsupplies.co.uk/product/117...


https://www.autoelectricsupplies.co.uk/product/116...

[Paulytrewq]

Great thanks - hopefully reduce susceptibility to corrosion 👍