WR engine oil pressure relay for voice check

[Darron Edwards]

Having had an issue with my ur quattro oil pressure light, I've decided to put what I've learnt on here with the view that it might help others. It started when I found that a temporary wire had been run to the oil pressure switch. Someone had cut the wires that come from the oil pressure monitor relay (234) and run a single wire from the blue/black *(0.5) wire, *into the engine bay. It was connected to the black oil pressure switch. The reason that this was done was probably due to the engine being changed. A GA chassis car doesn't have oil pressure switches, but relies on a potentiometer (035919561) in the lower hole in the block. The upper hole is blocked off with a blanking plug (N0160241). Other WR engine quattros, particularly early cars, either have a one wire system wired straight to a bulb, or if the car has the earlier voice check, it uses a two wire system. On the early voice check version, the two switches are wired directly to the voice box. I couldn't find a diagram that relates to GA chassis cars on Phils website, only voice check diagrams for two wire systems. The MB oil monitor diagram was exactly the same. Below, I've included a photo showing the relay involved


This is the potentiometer with terminal G connected


Diagram in the MB section on Phils website showing the wiring arrangement. Terminal S on the relay is not connected to anything.


Wires showing the repair that I had to do now that Ive fitted the correct sender unit for the car.

[george21]

Very good info there, that is what I'm after now.
Can you write what goes where, as I'm not sure at the moment.
It is total of 4 wires for oil info
1. Oil temp, next to front engine puley
2. 0.25 bar low pressure sensor on the side of the block.
3. Just above it vdo sender with two wires one is G oil pressure to gaugeand another one WK 1.8 bar switch.
Problem is I can't figure out what goes where as its only one bulb in the dash and its three wires for that!??

[george21]

Oh and I'm dealing with wr 1985 with later voice box
Pre fix -E- on part number of voice box. I hope you can help

[Darron Edwards]

H mate, what I know so far is that only one wire goes on to the potentiometer. This is a blue and black wire at terminal G, and goes to the relay behind the glove box. The oil temperature sender wire is completely separate to the oil pressure wires and goes to the display in the centre console. You should only have two wires in the engine bay, one to the oil temperature sender and one to the oil pressure potentiometer.

[Darron Edwards]

Originally Posted by george21

Oh and I'm dealing with wr 1985 with later voice box
Pre fix -E- on part number of voice box. I hope you can help

What chassis is your car mate. FA or GA?

[george21]

it's FA chassis mate. there are two sensors for oil pressure as i understand. both of them on the block of the engine right? 1. two single pin G and WK VDO
2. single pin sensor just under the VDO sender.
so what goes where? as my wiring is a mess.

[Darron Edwards]

Where the loom comes alongside the block, how many wires have you got bud. There should only be one Black/Blue wire. The other wires are for water temperature senders, injector blower and warm up reg.

[george21]

it is a bit more complicated as i got 20v aby engine in my ur. problem is, aby engine have 3 wires for oil pressure warning system and wr engine as you stated only 1. and i'm trying to figure out what goes where. i can't see any relay with 234 on it in my wiring loom.
and i don't know what wires goes to it and how this relay works.
all i have is one wire coming from engine bay and if i conect it to dash bulb then voice kicks in attention! check oil level.
i told you is more complicated...

[Darron Edwards]

Right, I see. Ok the relay is there as a monitor. I'm not sure if it has an internal buzzer but it is not just a rely inside, it has loads of electronics. I would say that your car should have one somewhere unless you have two oil pressure wires. If you do have two, then they will go to the voice box (according to diagram on Phil Paynes website)

[george21]

Originally Posted by oldsynth

Right, I see. Ok the relay is there as a monitor. I'm not sure if it has an internal buzzer but it is not just a rely inside, it has loads of electronics. I would say that your car should have one somewhere unless you have two oil pressure wires. If you do have two, then they will go to the voice box (according to diagram on Phil Paynes website)

in the engine bay i have total of 3 wires
G wire (goes to gauge) blue
WK wire (0.3 bar) black
and 1 pin sensor (1.8 bar i guess) round white rubber sleeve
inside the car i have black 4 pin conector where 2 wires ( black blue) joined together
one goes to voice box and one to the dash bulb.
if i connect WK to those blue black wires dash bulb goes of when engine running and everything seems fine but patricia kicks in and repeating every 2-3 min attention! check oil level. If i connect 1.8 bar wire patricia shut but light is on!
so to answer your question yes i have 2 oil pressure wires from two sensors, but that does not makes clear where they going to....