dash lights very dim

[86chevyk20]

I replaced all the bulbs in my dash in my 86 with new super bright 194s and i see that they are all working but they are super dim. And yes my switch was turned up all the way lol


What can cause they to be so dim?? Like very dim. Im thinkin maybe that printed circut is shot.

 

[robert8096]

Check the cluster ground and the voltage on the wire that feeds the dash lights coming off the light switch. I have seen the bright/dim part of the the light switch fail and cause dim dash lights. It should be around 11 to 12 volts on the wire with the switch turned all the way up.

 

[chengny]

Surprising - usually they go to full brightness and you have trouble getting them to dim down.

LED's do not respond well to dimming with a rheostat. They really need to be controlled using pulse width modulation (PWM).

Clean the spiral wound resistor coil in your light switch really good. Use some carb cleaner and a toothbrush.

Reassemble and power up the dash lighting. Try rotating the dimmer slowly to different positions and see if you can find a "sweet spot" - a level of brightness that you can live with. When you get a good level of illumination leave it there.

If you can't get them to brighten up going through the rheostat, run a (fused) lead to the gray wire that feeds the dash illumination. That gray wire also goes over to the backlighting for the HVAC control panel - it's easier to splice a feed in over there.

They will work but will always be at full brightness.

 

[86chevyk20]

where is the cluster ground??/ andyou mean test the wire going from the dimmer switch to the cluster to see if it has 12 volts???

 

[chengny]

Location of ground(s) and rheostat controlled power connection for instrument panel lighting:

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[robert8096]

where is the cluster ground??/ andyou mean test the wire going from the dimmer switch to the cluster to see if it has 12 volts???

Yes, just like it says in the top left hand portion of the above wiring diagram.

 

[86chevyk20]

i do have a brand new dimmer switch instlaled. i forgot to mention. I suck at electrical

 

[MrMarty51]

i do have a brand new dimmer switch instlaled. i forgot to mention. I suck at electrical

Lektrikalz is the toughest portion of a vehicle to learn and to diagnose, a few trial and errors and solving problems, using the wiring diagrams too and You`ll do OK. Juz saying.
Seems that after a while, wiring gets to be fun, at least to Me and I used to fall down in fright whenever I had to do anything electrical, unless it was of the simplest tasks.

 

[robert8096]

Are you getting 12v from the new switch? If so start looking at the printed circuit board on the back of the cluster. It could be damaged or dirty. Pull one of the lights and check and see what the voltage is at the light socket.