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[deviator]

I was wondering if anyone had come across this problem before....
1.6 53 plate Zafira with the electric power steering pump has stopped working. Before I got involved, the pump was swapped - no difference. I doubt both pumps are duff, although it was a scrap yard part.

So far main power lines and earth seem fine, but no life.
I've checked engine bay fuse 3 & 7 (As mentioned in the Haynes book of lies)
I've also checked fuse 23 in the main in car fuse box, with no faults found on any fuse. I can't see reference to a relay in the wiring diagrams, or pretty much anything else in the system that would cause this fault.

A little Googling suggested that the battery/alternator is potentially an issue. The battery is 2/3 months old and has a good resting voltage. With the engine running it was showing 13.8v ish, peaking occasionally at 14v. When under load the voltage dropped to 13.5v. As the internet suggested this system needs circa 14v to run, this was my first port of call. The althernator has been removed and cleaned is now a healthy 14v+, but still no steering.

Ignoring the fat power and earth, there are 3 wires going to a plug (control side), the haynes book suggests one is earth and the other two I've tried to follow back, but with little help from the wiring diagrams.

I'm trying to workout if these are left/right control wires (I doubt it) or more likely an activation wire and a pressure sensor.

I'm going to connect the computer up tonight (I didn't have it with me yesterday) to see what the ECU says, but was wondering if anyone has any further pointers/suggestions?

Thanks,

Dave

[STEMO]

When you say power and earth seem fine, have you done voltage/continuity tests? I would be tempted to put 12v across the pump and see what it does.

[Rods2]

Is it compatible with a 1.4 Astra, if so, borrow one to see if that solves the problem from a fellow OOFer who is 'up North'.

[Webby the Bear]

When you say power and earth seem fine, have you done voltage/continuity tests? I would be tempted to put 12v across the pump and see what it does.

This ^^^

STEMOs a knowledgeable chap when he's not insisting on being silly! 

[Webby the Bear]

...though just to add continuity tests are no good for fuses as I found out this week 

Stick your multimeter to ground while probing each fuse terminal looking for the voltage that should be going to it (battery voltage I presume for this system?)

[deviator]

Thanks for the replies.

I've tried 12v across the old pump and it didn't come alive. Granted it could be a knackered pump, however...
The 12v feeding the pump is constant, not switched as it's 80amp. The control wire with 3 pins needs to be energised somehow and I don't know which pins to enable and if they need 12v or negative.
I have probed the output wire from the engine bay fuse (stuck probe through the insulation) and got a solid 14v with the engine running.

This leads me back to needing to understand how to 'enable/engage' the pump. If I can work this out, I can test it on the old pump first, before trying the pump in the bay.

Unfortunately the Haynes book of lies only mentions two wires, even though the PS Pump section (removal/refitting) mentions the later ones have three wires and an adaptor is available from VX.

If I could trace these wires back, it would be a start! But the wiring diagram is uselessly vague, or I'm being stupid.

[Webby the Bear]

I am still learning car electrics (and learning new things everyday as per the continuity fuse test thing  )

however if you've bypassed all the trigger/engagement stuff and shoved 12v straight to the pump and its done nothing does that not mean a dead pump? 

again, sorry if ive missed summat as im still learning 

[STEMO]

I am still learning car electrics (and learning new things everyday as per the continuity fuse test thing  )

however if you've bypassed all the trigger/engagement stuff and shoved 12v straight to the pump and its done nothing does that not mean a dead pump? 

again, sorry if ive missed summat as im still learning 

There's more than just two +ve and -ve connections, the pump has to move in different directions, and you need to know which one is ground.

[Marks DTM Calib]

From memory there is two supplies  (one ignition and the big one permanent) plus a speed signal and the later ones got a diagnosis connection

[deviator]

But the wiring diagram is uselessly vague, or I'm being stupid.

Again, thank you for the replies! Unfortunately, I was being stupid. My excuse is about 3 hours sleep and then a 9 hour working day + commuting time.

When I sat down to eat something this evening, I realised I was misreading the diagram. There is a fat 12v (from the engine bay fuse box) and a fat chassis mounted earth. The diagram in the book only referenced a 2 pin plug in addition to this. I finally worked out what was going where. There is a black wire which goes to the F23 in the cabin, this needs to be tested for 12v with the ignition on. There is also a Blue/White wire, this goes to the the switch on the alternator and the battery warning light.

Now unless I've misread it AGAIN  if the black is 12v with the ignition on/engine running. Then the only other wire is the Blue/White one to the 8mm bolt on the alternator. As such, I'll throw a spare wire in and connect this directly to the alternator and the PS pump. If that doesn't do the trick, both pumps are knackered.

This makes sense as you don't want the pump active unless the ignition is on and there is a charge supplied by the alternator.

I think I have this right. 

[Rods2]

You could check the internet for that make and model of pump for any further information, providing their is a label with this information on.

[Andy B]

....
This makes sense as you don't want the pump active unless the ignition is on and there is a charge supplied by the alternator.

I think I have this right. 

Sounds right as when the aux belt belt breaks you lose the power steering (on a diseasal Astra G) ............ which makes steering them bloody hard work

[terry paget]

As a matter of interest, is the power assistance the same as on an Omega, except thet the pump is electrically driven, not from a belt of the crank pulley. And if so, is this to make the engine more efficient by eliminating the constant drag of the omega power steering pump?

[deviator]

I will update in case anyone else has the same problem.......
The black wire is 12v live with the ignition.
The blue/white wire becomes live when the engine is started.
The spare wire is brown and an earth it appears.

Therefore I deduce the pump is at fault. I will update when the breakers yard swaps the pump and confirms it.

Terry, I think the idea is partially emissions and partially fuel economy. With no steering at idle, you don't have the drag of a PS pump. By the same token, when reaching the higher end of the rev range, a standard PS pump is still causing drag, but the pressure switch limits it anyway. Therefore the hydro-electric idea is you only get draw when the steering is in use and it 'cheats' the emissions.

[terry paget]

Thanks Deviator. 'Tis as I suspected. It's similar to the way cooling fans used to run direct from the crank pulley but are now electric.