Dash light dimmer switch issues

[cdslyde]

My 1989 chevy K2500 dimmer switch only works as on or off, does not dim. I first thought that I did this when adding LED dash lights, but I notice the heater control does not dim either. Does anyone have any advice to troubleshoot this issue? Is there a way to test the dimmer switch? I don't think it is the dimmer switch because I have two that do the same thing, but it is worth checking this out if there is a way to test the switch.

 

[AK49BWL]

It's the LEDs. They don't require much power to illuminate and the dash dimmer is made for higher current incandescent bulbs. If you replaced all the cluster backlights, there's no longer enough current draw for the factory dimmer to do anything, even with the other backlights. Only permanent fix with keeping LEDs is to replace the dimmer with a PWM controller.

 

[GoToGuy]

That's the reason LEDs can have same light output between a wide voltage range.

 

[cdslyde]

It's the LEDs. They don't require much power to illuminate and the dash dimmer is made for higher current incandescent bulbs. If you replaced all the cluster backlights, there's no longer enough current draw for the factory dimmer to do anything, even with the other backlights. Only permanent fix with keeping LEDs is to replace the dimmer with a PWM controller.

This is not due to the LED's. I put the stock lights back in and still dimmer only works as off or on, with no dimmer.Back to my original question, does anyone know how to troubleshoot this? Is there a way to test the dimmer switch?

 

[Scooterwrench]

The resistive strip in the dimmer has worn through. Only way to fix it is with a new dimmer.
It is written in the instructions that came with my aftermarket gauge set that the LED's could not be dimmed in the conventional manner but I wired them up with the stock illumination wire anyway and they would dim with the stock dimmer. I wound up wiring them to the ignition wire to burn all the time because the gauges were hard to see in the daytime when they weren't lit.

 

[cdslyde]

The resistive strip in the dimmer has worn through. Only way to fix it is with a new dimmer.
It is written in the instructions that came with my aftermarket gauge set that the LED's could not be dimmed in the conventional manner but I wired them up with the stock illumination wire anyway and they would dim with the stock dimmer. I wound up wiring them to the ignition wire to burn all the time because the gauges were hard to see in the daytime when they weren't lit.

But I have two different dimmers that don't dim. I was hoping there was some kind of test to run on the dinner to verify, otherwise I feel like I am throwing money at with Hope's a new one fixes the issue.

 

[caminonut]

I would think you would be able to do a continuity test on your dimmer switch to see if it has continuity as you roll the switch from on to its lowest point of dimming.

 

[Scooterwrench]

Use an ohmmeter connected to the terminals that correspond with the brown and green wires on the back of the dimmer. It should have high resistance with the knob rolled down in the dim position. The resistance will gradually decrease as you roll the knob up.

 

[cdslyde]

Use an ohmmeter connected to the terminals that correspond with the brown and green wires on the back of the dimmer. It should have high resistance with the knob rolled down in the dim position. The resistance will gradually decrease as you roll the knob up.

The ohms test sounds correct to.me. However, I did get a.third switch that was used for free and that worked. I still plan to.try this test and compare the working and non-stop ing switches.

On another note, there is some LED's that dim. I.know this because I have some.