Oil Warning Light - MB Engine

[sevans@radstone.co.uk (Steve Evans)]

Phil,

Thanks for your posting of the "Procedure for checking oil warning light - MB engine" of 6 June. It has led me to suspect the sender (G10), as its resistance with the engine off is a little high at 17ohms. At over £70 for a replacement I would like to confirm these suspicions. I have, for some 3 weeks, had a voltmeter monitoring the output of the sender, waiting for the light to come on, and last night it eventually did. The reading stayed at ~4.8V which is what I normally see at anything above 1600rpm. However I then noticed that when idleing the reading was ~3.7V rather than the 2.8V I normally see. I guess that this means that the problem lies either with the sender or whatever drives it. Had the wiring between the two gone o/c then the reading should have dropped to 0V. I shall have to experiment and find out at what dummy sender resistance (and hence voltage), the controller believes the wiring to have gone o/c; which the procedure states, results in the light coming on. 

The controller (J114) appears to have no direct connection to the oil pressure sender (G10). It is, as far as I can determine, the same control unit as used in later Audi 200s and is shown in the Haynes manual for said vehicle. This unit is, I believe, intended to be used with two switches, one at 0.3 bar and the other at 1.8 bar. Does the urQ have a 0.3 bar switch (and if so where)? What processes the signal from the sender (G10) and drives J114?

The near-side rear track control arm of my urQ has a shot outer ball joint and thus needs replacement (at £117-00 +VAT - ouch). I may be able to borrow some optical alignment kit to get the new one adjusted appropriately, however I do not know what the alignment figures are for an '88 urQ. Could you perhaps post the suspension settings for reference - just the sort of stuff for the FAQ. 

Thanks,

Steve  
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Steve Evans                             Radstone Technology Plc.
Principal Design Engineer               Water Lane,
                                        Towcester,
Tel: +44 (0) 1327 359444                Northants,
Fax: +44 (0) 1327 358113                NN12 6JN
Email: sevans@radstone.co.uk            ENGLAND