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Old 09-28-2021, 04:57 PM   #2
hatzie
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Join Date: Oct 2008
Location: Wentworth, NH
Posts: 4,916
Re: H/L & 4WD Switch-Dark,No See-um

You can replace the illumination lamps. They're around 4mm tungsten filament bulbs with blue silicone caps soldered to a circuit board or in a holder.
You can use LEDs but the light won't match the rest of the dash and door switch lamps. The tungsten bulbs typically last around 15 years so they'll outlast your ownership of the truck.

I did my headlamp switch. The dimmer got flaky a few months later so I replaced the switch. Didn't even think to look at the solder connections. The switch was pretty nasty so I didn't really want to keep it. The illumination bulb is mounted in a little 1/4 turn holder.
IIRC the switches were not expensive at all.


The plastic on the 4x4 switch was super brittle and it cracked even tho I used guitar picks slid down along the sides between the inner and outer parts of the switch body to release the plastic from the projections rather than push the plastic wide with a spudger.
The bulbs and switches are mounted to a super thin printed circuit board inside.
The other problem is the 4x4 switch has high density .010 pin pitch connectors that are molded into the rear of the switch housing.
To replace the bulb you need to desolder the PC board from the connectors and once the bulbs are replaced you need to solder the board back to the connector pins. I would highly recommend that you use a vacuum desoldering station. The switch board is super thin and it doesn't dissipate heat as well as a standard thickness board and the density of the pins is such that it's difficult to get all the solder out of the holes with braid and/or the spring-loaded solder suckers. You'll end up with lifted and torn pads without the proper tools.
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.

Last edited by hatzie; 09-29-2021 at 03:27 PM.
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