electrical wizards?

Question

I've posted before about my son's oil light problem.

Comes on only when engine is fully warm and then goes off and on randomly- oil pressure checked with guage on long test drive and is marginal, but not critical.

Last week his auxillary fan died. It was a mechanical failure & finally overheated the circuit bad enough to blow the 40A fuse under the steering wheel.

I changed the fan and took it for a test drive this morning. No oil light. . . Ever. . . I drove and drove and drove. . . . .[maybe I'm starting to like test driving my son's Audi too much.

So--- Is it possible that the hot wires/circuit from the fan was cooking a transistor, resistor or some such. . .. or did I hit a wire while routing the fan cable harness? The wiring was definitely cooking before it blew the 40A fuse--- When I was testing the bad fan circuit I blew the fuse & burned my fingers when I pulled it.

Thanks, Jim

Steve Sears · Accepted Answer

Jim,Depending on the location of the oil pressure sensor wires relative to thefan harness, mutual harness burning may be possible, and damaging the sensorsystem while changing the fan is a definite possibility - BTDT too manytimes.  Could the car have been running too hot before the fan replacementthinning the oil too much and causing a low pressure (is the coolant templower now?)?  Does the oil light come on when the ignition if first turnedon? Maybe check the pressure again with a gauge to see if there are anychanges.Cheers!Steve Sears1987 Audi 5kTQ1980 Audi 5k1962 and '64 Auto Union DKW Junior deLuxes(SPAM Blocker NOTE: Remove SHOES to reply)

Jim Elbrecht · Answer

As I reread my message I see how I misled you. I didn't *cause* a problem-- I seem to have *fixed* it! It was scheduled for a trip to the dealer in part to see if they could come up with a cause for the [apparently erroneous] oil pressure warnings.

The light still works when I have the car on acc --- but it isn't coming on while the car is running.

And, yes the oil sensor is right near where the wire harness goes, though I haven't followed the wires to see if they touch each other.

And as far as overheating, the coolant temp guage was running perfectly on dead center while the oil light was acting up. The day it overheated it went pretty far to right but never pegged--- and we were just a block from home so it was only hot for a bit.

Jim

Tony · Answer

Interesting.I think that you should tell your son that it is important for you to 'test' his Audi for a bit just to be sure it is corrected. Lots of country twisty roads and aggressive driving for a month or two should help with the answer. :-)Jim Elbrecht wrote:

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