Sierra Instruments.

[Guest Kieran]

Noticed that the indicator warning and oil pressure light not working today. Changed bulbs, still not working. Tried to follow the "haynes book of lies" wiring diagram but its not very clear.

 

If I touched a earth wire to the bulbs, they both worked. Bad earth me thinks. Then accidentally touched the alternator warning light . With a flash, it went out. Didn't blow, but popped fuse 22. Replaced said fuse, alternator light not come back on. Tried all other fuses, ok.

 

What have I nuked?????

 

Kieran

[Longboarder]

What year sierra donor are you using as fuse 22 does different things for different years. The oil, ignition and handbrake lights share an ignition live feed (but are completely separate from the indicators) and go respectively to earth through the oil press sensor on the block, excite the alternator or earth through both the hand brake switch and/or low fluid sensor. Have another look at what is and isn't working cos you still have the original fault(s) plus the new one!

 

Nigel

[Guest Kieran]

Its a 1987 Sierra GLSi donor.

 

Kieran

[Longboarder]

OK, amongst the things 22 does is supply the feed to contact 7 on the instruments which powers the warning lights, rev counter, temp and fuel gauges. Replace the fuse and if any of the above work then the fault(s) is in the instrument cluster or on toward the sensors. With ignition on, if you pull the wire off the oil pressure sensor and earth it to the block the oil light should come on. If it doesn't, earth it to the chassis. If it now comes on, check the engine to chassis earths.

If it still doesn't come on you need to closely examine the copper tracks on the back of the cluster to see if any are burnt out.

 

Nigel

[Guest Kieran]

Right, back on the 2B.

 

Got alternator light back on, all gauges work properly, handbrake light works and the main beam warning light works.

 

If I pull the oil pressure wire of the pressure switch and earth it, the oil light comes on. Dodgy pressure switch??

 

The indicator warning light don't work no matter what I do, (bulb ok) even with hazards. The indicators and hazards work fine.

 

Any ideas??

 

Kieran

[Guest chris brown]

The indicator warning light don't work no matter what I do, (bulb ok) even with hazards. The indicators and hazards work fine.

 

1 Bad connection on ether pin 15 or 16 on instruments

2 Burnt or damaged printed circuit on back of instruments

3 Wire from pin 15 to R on indicator switch broken

4 Wire from pin 16 to L on indicator switch broken

It has to be one of these as you say the indicators work OK hope this helps.

 

I have had problems with mine but they stopped completely due to water getting into the hazard switch (silly place to have it in an open toped car)

[Longboarder]

As per Chris plus replace the oil pressure sender. You can test the printed circuit and indicator lights in situ. Pull the instrument plug off the back of the panel, feed 12v pos into connection 16 and earth connection 12. The left indicator light should come on. Then 12v pos into 15 and earth 12 again and the right indicator light comes on. If they don't come on the fault is the bulbs their contacts or the printed circuit. Earth to instruments is proven OK or the main beam light would not work. Effectively contacts 15 and 16 on the back of the instruments are linked direct to the right (Bk/G) and left (Bk/W) indicator circuits respectively and the connection could be taken off anywhere handy on those circuits.

 

Nigel

[Guest chris brown]

Not quite Nigel as I think Kieran said indicator light which makes it early 1987 and pins 15 and 16 are across the bulb so you could test the pannel by applying 12 volts to ether pin 15 or 16 and earthing the other (Haynes wiring diagrams 13.27 Exterior lighting. Models up to 1987 but the books do vary with different editions)

[Guest Kieran]

Yeah, Chris is right, I only have the one "ambidextrous" Indicator warning light. (well "dark" in my case....!!)

 

Kieran

[Longboarder]

Pre and early 87. Same as my own! I did check and assumed 87 onward with two lights. OK so test the panel and light by applying power and earth across connections 15 and 16. If it works and you are short of time for a fix still do like the last sentence. Link 15 to a handy BK/G from the right side indicator circuit (just tee it in)and 16 to a handy Bk/W from the left.

 

Nige

[Guest Kieran]

Thanks guys,

 

I just "tee'd" into the circuit and it worked a treat. Don't know where I lost the original signal connections.

 

How bizzare...................

 

Kieran