MB engine Ur quattro Orange dash oil pressure light

Colin Aitchison · 24-02-23, 02:33 PM

I was working on a friends MB Ur quattro, and was changing the engine oil, when I went to restart the car and was looking for the oil pressure light on the dash, to make sure it went out after a few seconds of running, and no oil pressure light, to let you understand the dash was not working correctly for many years and has recently had a fully working dash fitted, so my friend thought it may not have an oil pressure light, can one of you guys confirm if the dash has or has not got an oil pressure light.
Thanks in advance.

vagdream · 24-02-23, 07:21 PM

Colin,
Red warning light, top middle of display.

Colin Aitchison · 25-02-23, 05:34 AM

Thanks vagdream, so this could be an easy fix, like, bulb blown, or oil pressures switch faulty, or oil pressure relay / buzzer not working, do you have any working experience of the oil pressure wiring? normally two oil pressure switches on left had side of block below and behind thermostat housing, from memory the top one is the light on dash, can you confirm? I know if this was an old Ford you would just pull the wire off the oil pressure switch and earth it out to the block with ignition on and the light on dash would light up, light working, so problem would be the oil pressure switch.
Dose anyone have a wiring diagram for the MB engine? I have one for the 1980 WR engine Ur quattro, but I am positive the MB engine wiring will be different.

BackintheFold · 25-02-23, 08:10 AM

Check that the bulb is in place and working. Switch it with the handbrake light to test (or another light that you know works)

Try disconnecting the sensor wire from the bobbin on the side of the engine (near dipstick)
Then try earthing it which should turn light on.

Remove the oil pressure control relay and see what happens.
You can link the sensor directly to the warning light by removing the control relay and connecting two of the terminals in the relay socket (2 and 6). This at least will give you a warning before firing the engine up or when running if the oil pressure drops below 0.3 bar (if the sensor is working). Also try cleaning the terminals of the sensor.

The 5 pin relay is hard to find-worth trying to fix the one you have.
If it’s missing or not fixable, you can use a 6 pin with some re-wiring and separate sensors to mimic the operation quite well-search my post on the subject for more!
(Here http://www.classic-audi.co.uk/forum/...pressure+relay )

BackintheFold · 25-02-23, 08:13 AM

Also, I am looking for an orange dash. If your friend wants to sell his old one let me know (pm is fine)

Colin Aitchison · 25-02-23, 12:08 PM

Thanks for the info, sorry, dash was swapped to get replacement dash.

25-02-23, 08:10 AM	#4
BackintheFold Senior Member Classic Audi Club Member Join Date: Feb 2019 Location: Near an MB ur Quattro Posts: 1,190	Check that the bulb is in place and working. Switch it with the handbrake light to test (or another light that you know works) Try disconnecting the sensor wire from the bobbin on the side of the engine (near dipstick) Then try earthing it which should turn light on. Remove the oil pressure control relay and see what happens. You can link the sensor directly to the warning light by removing the control relay and connecting two of the terminals in the relay socket (2 and 6). This at least will give you a warning before firing the engine up or when running if the oil pressure drops below 0.3 bar (if the sensor is working). Also try cleaning the terminals of the sensor. The 5 pin relay is hard to find-worth trying to fix the one you have. If it’s missing or not fixable, you can use a 6 pin with some re-wiring and separate sensors to mimic the operation quite well-search my post on the subject for more! (Here http://www.classic-audi.co.uk/forum/...pressure+relay ) __________________ 2006 A3 (daily drive) 1987 MB ur Last edited by BackintheFold; 25-02-23 at 11:29 AM.

25-02-23, 08:13 AM	#5
BackintheFold Senior Member Classic Audi Club Member Join Date: Feb 2019 Location: Near an MB ur Quattro Posts: 1,190	Also, I am looking for an orange dash. If your friend wants to sell his old one let me know (pm is fine) __________________ 2006 A3 (daily drive) 1987 MB ur

24-02-23, 07:21 PM	#2
vagdream Grown up member Join Date: Jul 2015 Location: Llandudno Junction Posts: 166	Colin, Red warning light, top middle of display.

25-02-23, 05:34 AM	#3
Colin Aitchison Senior Member Classic Audi Club Member Join Date: Dec 2013 Location: Back home in Tillicoultry Posts: 1,315	Thanks vagdream, so this could be an easy fix, like, bulb blown, or oil pressures switch faulty, or oil pressure relay / buzzer not working, do you have any working experience of the oil pressure wiring? normally two oil pressure switches on left had side of block below and behind thermostat housing, from memory the top one is the light on dash, can you confirm? I know if this was an old Ford you would just pull the wire off the oil pressure switch and earth it out to the block with ignition on and the light on dash would light up, light working, so problem would be the oil pressure switch. Dose anyone have a wiring diagram for the MB engine? I have one for the 1980 WR engine Ur quattro, but I am positive the MB engine wiring will be different.

25-02-23, 12:08 PM	#6
Colin Aitchison Senior Member Classic Audi Club Member Join Date: Dec 2013 Location: Back home in Tillicoultry Posts: 1,315	Thanks for the info, sorry, dash was swapped to get replacement dash.