1st Gen 12A Oil level sensor.......HELP!!!!

[captainbizzaro]

Hi all,
 
Bought my beloved with a blown engine so bought a 12A off of Tim just to get me through the summer......everything is fine,she started straight away and settled down to a nice tickover no probs. BUT...after 5 seconds of running the oil level light comes on and the alarm goes off.
 
I\'ve checked and rechecked the oil level and it is perfect,I checked for continuity on the sensor and it is not going to ground but when I did the same on the cable that connects to the sensor it is showing it going to ground which I guess is where the problem lies.
 
Any ideas why this might be happening?
 
Cheers

[David Nock (RIP)]

Wiring diagram shows that the sensor goes to ground, presumably on low oil level. So perhaps you\'ve got an earth fault on the wiring. Cable is Black/Green between the sensor coupler and connectorX01 which seems to be the biggish one which lays against the nearside inner wing. From there its Yellow/Red up to connector X06 which seems to be behind the dash. For fail safe though perhaps mazda work it the other way round, so that a broken wire would set off the sensor?
Theres a further complication in that theres a diode at the back of the light connecting to the alternator warning system.
If you\'ve got good oil pressure and you\'re sure of the level, you can afford to experiment without damaging the engine. So firstly try and find out in which mode the level switch is working (fail safe or not). then experiment by grounding the wire to the engine. Depending on this you may be looking for a short, a broken wire or a faulty diode.

[captainbizzaro]

Cheers for that David, I\'ll try get a look tomorrow night if the weather holds out! I\'ll keep you posted. Thanks for taking the time to check out the wiring diagram.
 
Tim

[David Nock (RIP)]

Having looked at the diagram again, it seems certain that the level switch goes to earth on low oil, not on correct oil level. The Mark 3 gen 1 (1983 to 1985) also used a choke and check relay to test all the warnings at start up. This shouldn\'t enter your problem beacause a failed choke and check relay puts all the warning lights up.
My guesses are (first) the level switch and (second) the connector X01 on the wing\'s got corrosion. I wouldn\'t expect any probs behind the dash and diodes shouldn\'t fail. Good hunting.

[captainbizzaro]

Sorted!! Traced it to connector X01 all gacked up with damp cobwebs of all things causing a low but significant voltage leak to ground.
 
Many thanks for your help David,much appreciated!!

[David Nock (RIP)]

RESULT! I no longer feel like a boring old fart wondering what this Greddi and Apexi stuff is all about. I\'m useful again!

[captainbizzaro]

Ha,well it\'s nice to know there are fellow old school fans willing to lend a hand. FB all the way!
 
Cheers again mate.