Jump to content

Warning Lights Wiring


Guest Monty2556

Recommended Posts

Guest Monty2556

I've rebuilt an old RH based on a 1990 Sierra. I've removed the original Sierra instrutment cluster and replaced it with dials and a warning light unit. I've looked at the wiring diagram and thought it would be easy! Each warning light has been earthed and I assumed all I had to do was cut each wire from the multi plug and wire it into the other side of the warning light based on the colour given in the wiring diagram. The indicators work, no problem. The high beam light just comes on with he headlights even when high beam not selected and the ignition and oil pressure lights just don't illuminate. What have I done wrong?

Link to comment
Share on other sites

On my warning light bank from cbs the main beam and indicators are earthed the orthers just have the live in one side then on to unit

Such as alternator/ charge light

Has positive in one side then orther goes to alternator for the ignition feed when gets live each side of light it goes out

Basicaly what templer above said

Link to comment
Share on other sites

Hi Monty,

If you look at this link below, it takes you to build tips and helpful hints.

If you look at clocks, it will show you what colour wire does what.

Looking at it, I would say the yellow and black needs to be split 3 ways for the Rev counter, oil press and ignition lights.

On the output side the oil press switch produces an earth return and the alternator produces a potential difference

 

I hope this is some help to you.

 

http://nw.rhocar.org/build%20tips1.htm

Link to comment
Share on other sites

Can I ask what type, tungsten or LED, warning lights you are using and secondly which functions do you want to have? Please list them.

If tungsten bulbs then it's all fairly logical as above. If LED then it's a bit different.

Edited by Longboarder
Link to comment
Share on other sites

LED not bi directional.

Clue Light Emitting Diode.

A diode only works one way.

Ignition on old type system needs to work both ways

Oil pressure switch shorts to earth so needs a switched live feed.

Later sierras had headlight switches connect the earth so warning light needed a switched live feed as well.

Edited by IanS
Link to comment
Share on other sites

LED can be made to work, just takes a bit of fiangling.

easiest way for ignition light is to have 2 LEDs in that position.

Wire in parallel but with the second LED the other way round (flat facing the other way)

Link to comment
Share on other sites

You need to be a bit careful with the ignition light. It is set up so one side of the light is fed by a 12V ignition switched feed. The other side goes to the alternator, which when you first turn on the ignition is not working so it as 0V. So the light goes on. Once you start the engine the alternator generates the 12V (actually nearer 14V) so the light now has the same voltage both sides and therefore goes out.

 

However, on most alternators the current flowing through the light is also used to 'excite' the alternator coils. If you only have an LED light then it is quite likely there will not be sufficient current flowing so the alternator will never start. The simplest solution is to have a 'normal' warning lamp in parallel to the LED, which you can hide away behind the dash.

Link to comment
Share on other sites

So alan how best way of doing that off terminals on led or piece into wire and doing this will it turn the dash led on and off which one as below

 

6yk2dt.jpg

Edited by jaimo
Link to comment
Share on other sites

Just goes to show an LED is not better than a tungsten in this situation. One way flow, sensitive to small voltage differences and may not allow enough flow to excite the alternator. Wiring a typical ignition light tungsten bulb in parallel with the LED should work. I can't guarantee the LED won't glow slightly even so, if there are any slightly high resistance wire joins in the circuits. Your right hand circuit is good.

 

Nigel

post-21-0-53590000-1521993013_thumb.jpg

Edited by Longboarder
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...