64 replies to this topic

[Tonylamb]

Last night I changed the old Japanese oil pressure gauge for a nice smiths one to match the other dials.  new braded pipe looks great in the engine bay.  expensive £20 but worth it.  Plugged it all in and started engine to check oil pressure working.  It does.  

 

Except RED LIGHT now not going out again  ARRRRGGGGHHHH

 

The B post on the voltage stabiliser is slightly loose so I'm wondering if that is the problem, i.e. intermittent power from the stabiliser.  I'm assuming the red light would be on even if there is no power from the stabiliser because its getting juice from the alternator???  or is that wrong.  

 

Frustrating.

[gazza82]

Did you touch the connections on the back of the alternator while changing the oil fittings? Sounds like you have a dodgy connection there. The ignition light is powered from fuse box and small connection on back or alternator. The two voltages cancel each other out and light goes off. One side is too low or no volts at all.

[Tonylamb]

I don't think so but its an interesting point, perhaps I should check the connections in the plug at the back of the alternator.  A dodgy wire there may have been the issue all along.

 

It can't be the voltage stabiliser because thinking about it the other side of the ignition light has to match the power from the alternator at 12v rather than the 10v that comes from the stabiliser.  Which it does.  so I think that rules out that issue.

 

I only let the engine run for long enough to get an oil pressure reading so its possible I didn't have enough revs on the alternator to put the light out.  But my memory is that it should go out almost instantly when the engine fires.

[gazza82]

Stabiliser is only for temp and fuel gauges ..

 

It goes out when the volts out of the amp hit about 12v .. that should be OK on idle with an alternator but if the idle is very low, it may flicker

 

It may even be corroded or broken wires where the attach to the spade terminal on the back.

[Tonylamb]

Put the new temp gauge in and that works. Also earthed the fuel gauge sender and that gauge works. Pulled out the alternator plug and checked the wiring all good. Started up red light out oil pressure working disnt run long enough to see temp gauge will do that Saturday. Thanks for everyone's help.