[INFO] Bulb numbers for 88-94 LED conversions.

[Vandyguy18]

When i was doing research for bulb numbers and such for my LED conversion, I found TONS of info for the 95-98 interior/trucks, but no consistent/useful info for the 88-94's like mine. Here is what I've gathered (and successfully tested) so far.

For future reference, pay attention to the number at the end of the four-digit bulb numbers. "6" means single intensity (always in "high" mode, like the under-dash lights), and "7" means dual (high AND low, such as turn signals)

Also, the ones that start with a "1" (such as 1156/1157) are CIRCULAR base bulbs, and the ones that start with a "3" (3156/3157) are the FLAT-BASE bulbs.

Front parking lights/Turn-signals: 1157

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Front corner lights (reflectors): 194

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Under-hood lights: 1156

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Two bulbs under dash, pointing down towards floorboard: 1156

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Gauges: 194 (SEVEN of them, unlike the SIX for the 95-98 trucks) plus the twist-locks for them, since the stock bulbs are soldered into the twist-locks (can be found on SuperbrightLEDs.com for cheap)

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Dome light: 578 Festoon Style bulb

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Map lights: These are the festoon style with the little hooks on either end, don't have the bulb number since i didn't replace mine.

STOCK GM TAIL LIGHTS: For the 88-89 trucks, they are 1157 for the top two bulbs, changed in '90 to the 3157 and 3156 for reverse (thanks 88GMCTruck for that info!) EDIT: Paragraph removed until i can do some hands-on testing on the circuit boards, should be re-written within a day or two!
Let's continue...

Reverse: You can use either a 3157 or 3157 in this spot, doesn't make a difference (I am running 3157's and they work great), BUT, be aware of the limited space behind the reverse lens, don't order a (for example) 82-SMD bulb, it is very long and WILL NOT fit.

License plate lights: I have been told by multiple people that these should be 194's, but i pulled mine apart and found 1156-base bulbs. CHECK BEFORE YOU ORDER. Here is what my plate lights look like (kinda hard to see, but looks like the wires were cut then re-spliced together, therefore i have reason to believe that my plate lights are NOT OEM)

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But as i mentioned before, TAKE THEM APART and check for yourself, just to be safe!

Oh, and just a little bonus fact, if you plan on installing an LED tailgate bar, the proper size is 60" bar for the fleetside (straight-bed) trucks, and 49" for the stepsides.

As I mentioned before, it is possible that your bulb numbers DO NOT match up with mine (maybe your truck's previous owner spliced in a different socket for a certain bulb for convenience) so i urge you all to DOUBLE-CHECK before you order bulbs. I am not responsible if you order the wrong bulbs because you didn't check before you order.

What about the cargo light mine is two pronged can't cross reference it with out number

 

[Vandyguy18]

What about the cargo light with the two prongs 88,- 94
Gmc Sierra SLE

 

[df2x4]

Did you try Sylvania's replacement guide? What do you mean by "cargo light with 2 prongs?" Are you talking about the dome light? If so it's a 211-2 festoon.

http://www.sylvania.com/en-us/applications/automotive-lighting-systems/Pages/lrgallbulbs.aspx?year=1994&qual=655&model=2795&make=18