What are the elec connections on the P Steering pump?

IdahoDoug

So, I noticed one of the connections on the PS pump has broken off. I checked the Bentley and in the exploded diagram of the pump, there is no mention of these connections. Anyone have any idea what they are? The system seems to work just fine.

Thanks.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

Merian · Posted: Sun Aug 30, 2015 7:59 pm Post subject:

I bet they tell the idle control module to raise the idle if racked out - but check to be sure

or maybe they also go to the ECU

jetpoweredmonkey · Posted: Sun Aug 30, 2015 9:25 pm Post subject:

Correct, that is a switch which closes to tell the Digifant system to bump the idle speed at full lock.
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1991 Westfalia 2WD

IdahoDoug · Posted: Sun Aug 30, 2015 9:27 pm Post subject:

Ah, thanks. No wonder I never noticed an issue. I'm a stickler for NOT hitting the ends of steering travel and continuing to steer. It's rough on things. I will reconnect it before our trip, though - it's a good thing to have.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

syncrodoka · Posted: Sun Aug 30, 2015 9:49 pm Post subject:

That pressure switch absolutely is in the bentley in the electrical section.

IdahoDoug · Posted: Sun Aug 30, 2015 11:43 pm Post subject:

Yeah, thanks. Oddly its not in the Power Steering Pump section. No mention of it and nothing in the diagrams. But thanks for "steering" me to the elec stuff where I found the circuit. Of course, it seems like the wire colors are wrong, but one of them is still connected so I have a clear course of action with the broken wire.

It looks like just a simple open/closed switch, eh?
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

danfromsyr · Posted: Mon Aug 31, 2015 6:03 am Post subject:

I believe the pressure switch is more for when the PS fluid is cold and slow to not bog down a cold idling motor.
it's just a simple switch, in fact you can use that 'circuit' to create a false high idle if/when needed by parallelling the wires thru a manual switch.
i.e. for charging or cooling circulation.
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jimf909 · Posted: Mon Aug 31, 2015 2:23 pm Post subject:

This got me curious, so while I was out putzing with the van I tried a few tests.

2.1 wbx with power steering, engine warm, A/C off, normal idle speed 950 rpm, trans in neutral, pkg brake engaged.

Start engine, turn the steering wheel. The idle speed drops about 75 - 100 rpm to ~850 rpm. Continue turning the wheel and at about 90 degrees the idle speed increased to ~1075 rpm. The idle speed then remains at ~1075 as long as I kept turning the steering ever so slowly all the way to lock. Stop turning the wheel and the idle speed returns to 950 rpm. Resume turning the wheel and idle speed returns to ~1075 rpm.

Next, I disconnected one wire lead at the PS pump and turned the wheel. The idle speed dropped to about 850 rpm (75 - 100 rpm slower than normal idle speed) and never returned to 950 as long as I continued turning the steering wheel.

Result: it seems this switch is activated when the pump is engaged and increases the idle speed about 75 - 100 rpm.

YMMV, etc.

p.s. I don't think a full 90 degree turn is required, that was just about as long as it took the switch to engage after initiating the turn but I certainly don't know for certain what those wily germans have programmed into this machine.

(Now I've got to clean the rubber scrubbed off my tires off of my new driveway. Oy, science has a cost.)
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- Jim

jetpoweredmonkey · Posted: Mon Aug 31, 2015 2:39 pm Post subject:

To clarify...this is just a simple pressure switch not unlike the oil pressure monitoring switches. It doesn't respond to steering angle, but to hydraulic pressure. Thus it will close whenever the pump produces enough pressure, due to reaching the steering travel limit, cold fluid in the circuit, or any other dynamic conditions that cause the pressure to increase.
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1991 Westfalia 2WD

jimf909 · Posted: Mon Aug 31, 2015 3:14 pm Post subject:

Yep, in my van just turning the steering wheel and continuing to turn it ever so slowly created enough pressure to engage the switch to trigger an increase in idle speed.
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- Jim

shadetreetim · Posted: Mon Aug 31, 2015 4:32 pm Post subject:

If you meter those wires, one is simply 12V+. The other, as has been previously disclosed, goes to the idle control.
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Tim Potts

Doing my best every time I drive it to dispel the myth these Vanagons have to be slow!

'89 Vanagon Bluestar/Country Homes 1.8T & .77 4th
'74 Jeep CJ5

crazyvwvanman · Posted: Mon Aug 31, 2015 4:39 pm Post subject:

You need to be careful with the 12v power wire to the PS switch because heaven help us there is NO FUSE and if it gets a sustained short to ground it will fry the FI harness. Design defect IMHO but that is what we have.

Mark

Zeitgeist 13 · Posted: Mon Aug 31, 2015 4:51 pm Post subject:

Mine shorted out years ago, so I trimmed both melted wires back to the harness, and screwed a threaded blank into the hole. I've been running without a functioning circuit for probably 6 years. Even at full lock I don't notice a bog on the engine
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

IdahoDoug · Posted: Mon Aug 31, 2015 10:35 pm Post subject:

Mark,

Thanks for the head's up. Will get that wire reconnected - thanks for the warning.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

boroko · Posted: Tue Sep 01, 2015 12:35 am Post subject:

I also torched a harness when that switch shorted to ground. As mentioned elsewhere, that power wire is a small gauge branch off a larger wire that is only fused for the larger wire. Personally, I add and inline fuse for that one in the black box so I don't have to go through that again. Simple enough, and saves a bunch of problems.

Bo
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'87 SyncroWesty: Smokey the Turtle, '85 SubiWesty: Chappie, '84 GTI, '86 GTI in full Rally trim,
previous: 2 Syncro tin tops, 2 Vanagons, 3 busses, 3 Ghias, 2 Jettas, a 411, a gas and a diesel Bunny and about 25 Beetles, one that only drove left.

Merian · Posted: Tue Sep 01, 2015 11:41 am Post subject:

I never assume that wires are fused on a German vehicle. I dunno what is wrong with the Germans & electricity, but...


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