Dash Lights

[Pastel Blue]

Today for the first time in 18 months since I started the complete rotisserie restoration, I dropped a battery back into the engine bay to test (initial) some of the reinstalled electric circuits. I bumped the starter to make sure it and the engine were ready to fire... good to go.

Heater motor, wiper motor, both ok

As I have not installed any of the exterior lights, I checked each plug end with a test light. Front and rear lights including side markers tested good. License plate light also good. Signal light indicators turn on, but are not flashing intermittent, same with the emergency flasher.

The shifter light works as do the two courtesy lights under the dash. However, at this time I have no other dash lights... I did switch them over to LED's (the shifter and courtesy lights as well which are working).

The car is in its infant stages of having everything working again, but I like the initial progress.

My question is should I be worried about no dash lights at this time or do I need to investigate further. I was confident that I installed the LED bulbs in the correct direction on the circuit board, but this is the first real test to see if they work...

 

[midlife]

Side marker lamps, shifter lamp and courtesy lamps are not on the dash lamp circuit. Did you pull out the headlight switch? Rotate it to fully on? Fuse good?

 

[Pastel Blue]

Side marker lamps, shifter lamp and courtesy lamps are not on the dash lamp circuit.  Did you pull out the headlight switch?  Rotate it to fully on?  Fuse good?

Yes, yes and yes... but I will check the fuse again today. I will look closer at the electrical schematic as well, which I had not done as of yet. Could be a bad head light switch?, although there is power to all the exterior lights when I pull it out. At this stage, my dash lights should have operated? If one led light bulb is installed incorrectly, will that cause all the dash lights to fail? Which means something is amiss... will research further and update. Thx.

 

[Carolina_Mountain_Mustangs]

Sounds like you already have the cluster installed. If you didn't there is a thread on the forum that has the printed circuit layout so you can bench test everything before install, much easier.

 

[Mister 4x4]

The power transformer on the circuit board could be bad as well.  I don't believe they work like some old Christmas light strings, either (one goes out, they all go out) since they're not wired in series, after all.

Unless the LEDs are specifically marked, you could feasibly have every one of them in backwards - I know when I did mine, they weren't marked very well at all (I thought a little 'nub' on one side of each LED was the '-' side indicator, and installed according to that theory.  Only a few of mine worked, and once I flipped them 180 in their sockets, all was good.

I believe the issue with your signal lights not flashing might have something to do with not having any bulbs in the sockets to complete the circuits.  If I'm not mistaken, the flasher works on resistance (closes the relay when the circuit is activated, builds-up resistance through the circuit as the lights are on, then opens the relay when the resistance is at the correct level, stays open while the resistance drops to a certain level, then closes the relay to power up the indicators, etc., etc.,) and without the circuit being completed, the resistance can't build to the level the flasher needs to function properly.  Or something like that.

I remember with my older cars learning that a signal bulb had burned out by the signal indicator simply turning 'On' and not flashing.  Replaced the burnt bulb, and it all worked again.

Little stuff - you'll get it worked out.  Better to find out these issues now, rather than after the car's all back together (kinda like I did some of the things I've been doing to mine). ::thumb::

 

[73pony]

Mister 4x4 is correct on the turn signals and flashers. There must be good bulbs in all sockets for them to flash.

 

[Pastel Blue]

The power transformer on the circuit board could be bad as well.  I don't believe they work like some old Christmas light strings, either (one goes out, they all go out) since they're not wired in series, after all.

Unless the LEDs are specifically marked, you could feasibly have every one of them in backwards - I know when I did mine, they weren't marked very well at all (I thought a little 'nub' on one side of each LED was the '-' side indicator, and installed according to that theory.  Only a few of mine worked, and once I flipped them 180 in their sockets, all was good.

I believe the issue with your signal lights not flashing might have something to do with not having any bulbs in the sockets to complete the circuits.  If I'm not mistaken, the flasher works on resistance (closes the relay when the circuit is activated, builds-up resistance through the circuit as the lights are on, then opens the relay when the resistance is at the correct level, stays open while the resistance drops to a certain level, then closes the relay to power up the indicators, etc., etc.,) and without the circuit being completed, the resistance can't build to the level the flasher needs to function properly.  Or something like that.

I remember with my older cars learning that a signal bulb had burned out by the signal indicator simply turning 'On' and not flashing.  Replaced the burnt bulb, and it all worked again.

Little stuff - you'll get it worked out.  Better to find out these issues now, rather than after the car's all back together (kinda like I did some of the things I've been doing to mine). ::thumb::

Yeah, the bulb thing makes sense, have had this issue before.

I bought the hipo led's and they are marked, so pretty sure they are in right, but did not try to bench test after install... if one led bulb is not working does this effect all in the cluster?

just now going to start trying to figure out the issue. I will look into some of the other comments here as well. 

My light switch is the original and I really don't like how it operates, the lever feels funny when pulling it out or turning, I have a spare may change it out to see where that goes. May pull the cluster out... and see if I can figure out how to bench test if need be. Electrical is basic for me, I am good at putting things back together as I found them, if they fail... we will do our best. I'll keep plugging along... I am persistent.

 

[73pony]

On the LED bulbs mine were all marked posit e and negative, however after reading a prior post on here I tested each individual bulb for correct polarity and found that 3 of them were marked incorrectly. Granted I ordered a cheap set off eBay from china.

 

[Pastel Blue]

I did test each bulb before installing and they were all fine.

Let me throw this out there... as I mentioned, the signal indicators work (they are new led's in the cluster). Also, as I have the idiot lights, when I turn the key to start both the alt and oil lights come on as they should (again, the oil light is a new LED, the alt light remained an incandescent as per mfr. specs ). So, some of the cluster lights are working, just not the remaining led lights to illuminate the cluster. These are the only lights on the car not working.

If it was the cluster circuit board none of the aforementioned would operate, correct? I did bypass the fuse on the box and still no go... I am pretty sure the fuse is ok.

Does this mean it is either the light switch or the circuit board transformer pac (although why do the other cluster lights work?). Trying to eliminate the issues one by one.

 

[73pony]

My guess is on the switch then. If you have a spare one it wouldn't hurt to swap it out to test.

 

[Mister 4x4]

I bought the hipo led's and they are marked, so pretty sure they are in right, but did not try to bench test after install... if one led bulb is not working does this effect all in the cluster?

No, the bulbs on the printed circuit are wired in 'parallel,' meaning that if one isn't working, then others will still continue to work since each side of the parallel circuit is independent of the other.  If it was wired in 'series,' then the first bulb that failed to complete the circuit would cause the whole thing not to work (like old-school Christmas lights).  I don't know how better to explain it - sorry.

I'm willing to bet you could literally turn on the lights, and unscrew each LED, flip the contacts 180 degrees, and re-install them, noticing that each one would then work... IF the issue of bulb polarity is the problem.

If it's something else (light switch, power transformer, bad ground in the wiring harness, etc.), then they won't work regardless of how they're installed.

FWIW - the indicator bulbs are on a different circuits than the dash light bulbs.  They have their own circuits which are tied to their specific sensors - not the illumination bulbs.

 

[Pastel Blue]

I bought the hipo led's and they are marked, so pretty sure they are in right, but did not try to bench test after install... if one led bulb is not working does this effect all in the cluster?

No, the bulbs on the printed circuit are wired in 'parallel,' meaning that if one isn't working, then others will still continue to work since each side of the parallel circuit is independent of the other.  If it was wired in 'series,' then the first bulb that failed to complete the circuit would cause the whole thing not to work (like old-school Christmas lights).  I don't know how better to explain it - sorry.

I'm willing to bet you could literally turn on the lights, and unscrew each LED, flip the contacts 180 degrees, and re-install them, noticing that each one would then work... IF the issue of bulb polarity is the problem.

If it's something else (light switch, power transformer, bad ground in the wiring harness, etc.), then they won't work regardless of how they're installed.

FWIW - the indicator bulbs are on a different circuits than the dash light bulbs.  They have their own circuits which are tied to their specific sensors - not the illumination bulbs.

understood... I will eventually retest the lights, just not yet ready to go through the trouble of accessing them. My comment on the indicator bulbs had to do with the fact that they are operated via the circuit board so if that was faulty, no lights attached to the circuit board would operate. As four lights do (signals, oil and alt), I am guessing the circuit board itself is ok.

Nope, I thought I had a spare light switch, turns out I have two wiper switches, great... 

i will pull the light switch and take a closer look at it to see if there is any obvious issues, I just realized that the light for the fan/heat selector is also not working, so I can't just state the problem as the cluster.

The car has few options/interior lights, the radio is out so that light can't be tested yet.

What I haven't figured out yet is what actually goes through the light switch to be powered. Common sense, the lights..., but why do some work and dome don't. There must be a problem in the old switch, although it did not show any obvious signs before I reinstalled it.

 

[73pony]

The accessory lights that go through the dimmer in the headlight switch are as follows...

Dash gauge lights (not working)

Fan/Heater lights (not working)

Radio Back Light (not hooked up but you could use a test light on the back lighting lead)

This all points the head light switch.

 

[Pastel Blue]

The accessory lights that go through the dimmer in the headlight switch are as follows...

Dash gauge lights (not working)

Fan/Heater lights (not working)

Radio Back Light (not hooked up but you could use a test light on the back lighting lead)

This all points the head light switch.

funny I was just looking at this in my electrical schematics... I will get a new switch and take it from there. As I mentioned, I was never happy with its operation, it was just tired and sloppy... I can be happy if this is the end result. Thanks

 

[midlife]

Does this mean it is either the light switch or the circuit board transformer pac (although why do the other cluster lights work?).

There is not circuit board transformer for the dash lamps. The circuit board voltage regulator is for your fuel, oil, and temperature gauges only.

 

[Pastel Blue]

Does this mean it is either the light switch or the circuit board transformer pac (although why do the other cluster lights work?).

There is not circuit board transformer for the dash lamps. The circuit board voltage regulator is for your fuel, oil, and temperature gauges only.

...Got it.

 

[Pastel Blue]

Success...

Nice to know looking back now, that I did put everything together correctly after taking everything apart to properly clean, lube etc.

In the end, the only thing that slowed me down for a day was a small copper tab that had been pushed away from the coil spring contact, probably when I had put it away for storage and then the final cleaning before reassembly.

Thanks to those who commented. On to the next project...

 

[Mister 4x4]

Sorry about that, Ken - I should've said "voltage regulator" instead of "transformer." And even then I was off-base. :whistling:

I knew midlife would've come along and set me right, though. rofl

Glad you got it figured out, nonetheless. ::thumb::