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dash light problem
#1
Hello,

i have a 73 convertible with dash lights that will not illuminate. I have checked all the fuses and they are good. When I turn the headlight switch all the way to the left the courtesy lights do illuminate. The dash lights don't when I pull the headlight knob/switch out to either the headlight or parking light position. I do hear an clicking sound coming from behind the dash. The headlights/parking lights do work. Sometimes when I turn the HL switch to the position to illuminate the courtesy light s they do not come on have to rotate back and forth to get them to come on. Before I start just replacing parts wanted to get some advice. Wonder if it could be a bad headlight switch ... thanks for your input.

steve
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#2
Steve, it sounds like you need a new switch, or clean the resistive contact on the switch you have, its the spring looking wire on the ceramic wheel, also clean the contactor, if you look at my pictures you see where the old switch has the green oxidation on the contactor, that touches the resistive spring.

here are some pictures I took when I replaced my switch, you can see how clean all of the contacts are on the new one, it also made my dash lights 200% brighter.


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Iyman
1972 Mustang convertible run_horse  
Visit the Mustang Car Club of New England Facebook Page

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#3
imusa76;194896 Wrote:Steve, it sounds like you need a new switch, or clean the resistive contact on the switch you have, its the spring looking wire on the ceramic wheel, also clean the contactor, if you look at my pictures you see where the old switch has the green oxidation on the contactor, that touches the resistive spring.

here are some pictures I took when I replaced my switch, you can see how clean all of the contacts are on the new one, it also made my dash lights 200% brighter.

Thanks for the pics, really appreciate it. I'll let you know how it goes !
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#4
tunes 
The switch is causing an issue so cleaning or replacing is a step In the right direction.

You may have 2 issues.

When the headlights switch turns on and the exterior lights are on, do any of the inside lights turn on besides the courtesy lights do the lights for the floor shifter, radio, heater control lights turn on, if the have a map light does it turn on.
If the radio and shifter light come on so there is some illumination then I would suspect the circuit board for the main instruments may need to be serviced or replaced possible bad connection with main harness.

If nothing comes on, then you have a more serious issue with a broken or corroded ground wire.

Do the gauges themselves work?


It could be possible that all the bulbs in the dash are not working correctly or blown out.

The bulbs are notorious for being impossible to see lit due to a bunch of reasons so you want to see if the bulbs are actually turning on.
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#5
72HCODE;194955 Wrote:The switch is causing an issue so cleaning or replacing is a step In the right direction.

You may have 2 issues.

When the headlights switch turns on and the exterior lights are on, do any of the inside lights turn on besides the courtesy lights do the lights for the floor shifter, radio, heater control lights turn on, if the have a map light does it turn on.
If the radio and shifter light come on so there is some illumination then I would suspect the circuit board for the main instruments may need to be serviced or replaced possible bad connection with main harness.

If nothing comes on, then you have a more serious issue with a broken or corroded ground wire.

Do the gauges themselves work?


It could be possible that all the bulbs in the dash are not working correctly or blown out.

The bulbs are notorious for being impossible to see lit due to a bunch of reasons so you want to see if the bulbs are actually turning on.
HI,

I do not have gauges, just idiot lights. When I pull out the headlight switch the headlights and or parking lights illuminate, depending on how far I pull out the switch. Whether I have the HL's on or off the HL switch will turn on the interior map light and under dash lights. Although sometimes, when I turn the HL switch hard to the left to turn on interior lamps ... they do not come on. Have to jiggle it or repeatedly turn the switch off and on to get the interior lights working. The fuses are good, have to check the dash lights again in a dark environment and see if the fuse I replaced had any impact. As far as I can tell it did not, but i will double check. Otherwise everything is dark except for the high beam dimmer light. (highbeams on Red Pony). Thanks
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#6
i would definitely replace the headlights switch and keep the original old one on the side for now.

Replacing the switch is not going to solve the issue but it will make diagnostics easier.

when you do test the lights, look for the accessories lights to the left and right of the steering wheel.
The lighter port, wipers switch, make sure those are lighting up when the lights switched is turned on.
then look at the center section of the dash above the transmission hump.

since you have a idiot lights car then you may not have the center 3 gauges. so look at the radio lights and clock if you have it and the gear selector,, if these are lighting up in some way then you know the circuit for the lighting is working.

basic operation of the head lights switch. it has 3 positions. all the way in is off. pull it out half way Dash lights and running/parking lights will turn on, turn it left or right for dimming, and all the way to one side and it clicks and turns on the door and courtesy lights for full illumination.
pull the switch all the way out and the headlights come on.

now the dash lights on these cars are a problem, age causes the blue light filters in the gauge cluster to turn black and you get almost no lighting from a new halogen 194 light bulb. so its possible they are lighting up but you can't see it.

I would test inside the garage, turn off all the lights, have a flashlight with you and test in complete darkness to see if something does light up or not on the main gauges.

now good chance you will need to pull the main instrument cluster out of the car, you might need to replace the main circuit board and you may need to replace the lighting sockets and lights themselves. but first you want to see if the electrics are working because if you go through all this work and it still won't light up then you have to really start digging into the dash harness for the broken wire.

i would recommend once inside the main cluster changing to Green LEDS and removing the blue light filters from inside the gauges. this will require taking many things apart carefully to make the modifications.

you might want to set aside a possible budget of 100$ or more to make repairs or modifications.

as a start i would budget for a definite headlights switch replacement.

now i would try to source an original switch which will be more money then a reproduction switch but there used to be issues with the reproduction switches not working or fitting the harness connector correctly. a nos switch used to run about 40$ while a reproduction was 15-30$

step #1 do a complete darkness test with the current switch and take note if any other inside lights are working when the switch is pulled.
step #2 replace the switch and retest.
possible
Step #3 removing the main gauge cluster and budget for a:

*new circuit board

*possible dash voltage regulator

*possible nos socket replacements(do not use the reproduction ones they do not fit or work right, the original black plastic tends to fall apart from the bulb heat and they need to be replaced, depends when you do inspection)
LED upgrade and removal of blue filters inside the gauges, this modification of removing the filters may not be reversible the plastic is brittle so when you try and remove the filters carefully the white plastic pins snap off and thus you commit to colored LEDS from that point on.

at least with step 3 you rule out problems with the gauges themselves and upgrade the lighting dramatically.
  Reply
#7
72HCODE;195007 Wrote:i would definitely replace the headlights switch and keep the original old one on the side for now.

Replacing the switch is not going to solve the issue but it will make diagnostics easier.

when you do test the lights, look for the accessories lights to the left and right of the steering wheel.
The lighter port, wipers switch, make sure those are lighting up when the lights switched is turned on.
then look at the center section of the dash above the transmission hump.

since you have a idiot lights car then you may not have the center 3 gauges. so look at the radio lights and clock if you have it and the gear selector,, if these are lighting up in some way then you know the circuit for the lighting is working.

basic operation of the head lights switch. it has 3 positions. all the way in is off. pull it out half way Dash lights and running/parking lights will turn on, turn it left or right for dimming, and all the way to one side and it clicks and turns on the door and courtesy lights for full illumination.
pull the switch all the way out and the headlights come on.

now the dash lights on these cars are a problem, age causes the blue light filters in the gauge cluster to turn black and you get almost no lighting from a new halogen 194 light bulb. so its possible they are lighting up but you can't see it.

I would test inside the garage, turn off all the lights, have a flashlight with you and test in complete darkness to see if something does light up or not on the main gauges.

now good chance you will need to pull the main instrument cluster out of the car, you might need to replace the main circuit board and you may need to replace the lighting sockets and lights themselves. but first you want to see if the electrics are working because if you go through all this work and it still won't light up then you have to really start digging into the dash harness for the broken wire.

i would recommend once inside the main cluster changing to Green LEDS and removing the blue light filters from inside the gauges. this will require taking many things apart carefully to make the modifications.

you might want to set aside a possible budget of 100$ or more to make repairs or modifications.

as a start i would budget for a definite headlights switch replacement.

now i would try to source an original switch which will be more money then a reproduction switch but there used to be issues with the reproduction switches not working or fitting the harness connector correctly. a nos switch used to run about 40$ while a reproduction was 15-30$

step #1 do a complete darkness test with the current switch and take note if any other inside lights are working when the switch is pulled.
step #2 replace the switch and retest.
possible
Step #3 removing the main gauge cluster and budget for a:

*new circuit board

*possible dash voltage regulator

*possible nos socket replacements(do not use the reproduction ones they do not fit or work right, the original black plastic tends to fall apart from the bulb heat and they need to be replaced, depends when you do inspection)
LED upgrade and removal of blue filters inside the gauges, this modification of removing the filters may not be reversible the plastic is brittle so when you try and remove the filters carefully the white plastic pins snap off and thus you commit to colored LEDS from that point on.

at least with step 3 you rule out problems with the gauges themselves and upgrade the lighting dramatically.

Hello,

Thanks very much for the detailed info. Might be some time before I get to this, but I will keep you posted ... thanks again !
  Reply
#8
imusa76;194896 Wrote:Steve, it sounds like you need a new switch, or clean the resistive contact on the switch you have, its the spring looking wire on the ceramic wheel, also clean the contactor, if you look at my pictures you see where the old switch has the green oxidation on the contactor, that touches the resistive spring.

here are some pictures I took when I replaced my switch, you can see how clean all of the contacts are on the new one, it also made my dash lights 200% brighter.

Hello,

FYI, I installed the new switch and the dash lights are working great ! Thanks, the original switch was falling apart ... very crusty.

Steve
  Reply
#9
great Big Grin

awesome news.
  Reply
#10
That's good news, easy troubleshooting Big Grin

[Image: 2zem9nk.jpg]
Iyman
1972 Mustang convertible run_horse  
Visit the Mustang Car Club of New England Facebook Page

Visit the Mustang Car Club of New England Web Page

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