dash light problem

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

naa10104

Well-known member
Joined
Jul 26, 2014
Messages
446
Reaction score
1
Location
Reston, VA
My Car
1973 Convertible, matching #'s H Code, Auto
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

 
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.

20140423_194500.jpg

20140423_194641.jpg

20140423_194543.jpg

20140423_194658.jpg

 
Last edited by a moderator:
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 !

 
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.

 
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

 
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.

 
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 !

 
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

 
I'm have a similar problem, but my light all go out including the rear taillights. The head lights stay on and so does the high beam indicator red light of the pony.

I have a new light switch. I'm installing it today. I hope it works.

I keep on hearing a click coming from in the glove box when the light goes out. Is there a relay in that area.

Anyone know what the problem may be with the lights?

 
How difficult is it to replace that switch? Moreover what needs to come apart, what is the disassembly procedure? I figured out you have to push a pin to get the shaft of the knob out. It looks like the whole assembly should plug into a socket. But how much of the dash needs to come apart to do that?

 
Last edited by a moderator:
How difficult is it to replace that switch? Moreover what needs to come apart, what is the disassembly procedure? I figured out you have to push a pin to get the shaft of the knob out. It looks like the whole assembly should plug into a socket. But how much of the dash needs to come apart to do that?
that was going to my question also.. mine are very dim, but everything works. i want to look into pulling the inst panel and replacing the bulbs too..

 
How difficult is it to replace that switch? Moreover what needs to come apart, what is the disassembly procedure? I figured out you have to push a pin to get the shaft of the knob out. It looks like the whole assembly should plug into a socket. But how much of the dash needs to come apart to do that?
that was going to my question also.. mine are very dim, but everything works. i want to look into pulling the inst panel and replacing the bulbs too..
Been awhile since I replaced my HL switch, but from memory it wasn't too hard, just awkward. Now, ANY time I need to work under the dash, I pull the dr seat out, 2 nuts 2 bolts and it's out o' there! If you have dim cluster lights, replace with Hi-Po Elite series LED's. This was recently posted on in detail. Do a search, top right. If you have idiot lights, DO NOT put an LED in the ALT socket. Just a regular bulb goes there. You'll be amazed at the difference. Also you can change color if you like. I preferred to keep the original hue with the blue caps. Others take these out as they are crusty or broken.

A worn out 40 something year old HL switch can definitely cause problems and they aren't too expensive.

 
How difficult is it to replace that switch? Moreover what needs to come apart, what is the disassembly procedure? I figured out you have to push a pin to get the shaft of the knob out. It looks like the whole assembly should plug into a socket. But how much of the dash needs to come apart to do that?
that was going to my question also.. mine are very dim, but everything works. i want to look into pulling the inst panel and replacing the bulbs too..
Googling answered the question:


 
Last edited by a moderator:
Back
Top