'89-'91 Suburban/K5 Blazer LMC Headlight and Wiring Upgrade Write Up with Pics


I had this write up over on a few other forums so I thought I would post it up here to share with the Chevy/GMC guys here.


I found LMC had the headlight upgrades that were actual glass with metal housings. They also offered a wiring harness upgrade. Now I had done this on my Jeep in the past so I knew it would have good results.

Parts required
#36-0302 Low beam
#36-0303 High Beam
#36-3582 Wiring harness (This harness is required for this headlight upgrade)
Sheet metal screws
Dielectric grease

Tools required
T-15 Torx drover
13MM socket
Drill bit

if you want to make permanent connections
Wire cutter
Crimp tool
Heat shrink
Butt connectors
Wire cutters
Crimp tools

First as usual disconnect (and in this case remove the battery) before working on anything electrical.

Headlights with the wiring harness. The wiring harness has a disclaimer boldly stating "This wiring harness is NOT intended to be a replacement to the existing wiring. It is intended to plug into your existing wiring components". Uh yeah right, that's why you don't sue any of your old connectors which also means not using the old wiring. Its a simple CYA disclaimer.

NOTE Added 10-2-12: The LMC harness comes VERY WELL labeled so you cant screw it up.

Low Beam


High Beam


Start by removing the four T-15 Torx screws to remove the headlight bezel. When you are ready to remove the bezel tilt the bottom and kind of pull down. the top screw mount is a tang up under the sheet metal be careful not to break it off.


The headlight itself is held in by a metal frame and four T-15 Torx screws. This is the same on all four headlights. Remove the four screws.


TIP: Loosen the two bottoms screws about half way out and then completely remove the two screws on top. This allows you let the headlight and capture frame sit on the lower screws so you don't need a 3rd hand. The capture frame screw holes are just notched so you can pull it right off the screws when ready to swap headlights out.


A view from behind the headlights. I ran the new harness across the top of the radiator support for now.


I used this grounding point on the drivers side for the harness. The bolt was too big so I cut off the grounding rings that came with the harness and crimped on my own larger ring to fit the bolt. This bolt uses a 13mm socket.


Same ground location on the passenger side. I also had to use a new ground ring for this bolt as well. Again, use a 13mm socket on the bolt.


Harness connectors come with each of the headlights and basically what they want you to do is unplug the factory connector and just slide the tangs into the existing plug. Bare connector from new plug on left. Factory headlight connector on the right.


Take a close look and you see bare metal still in the open asking for a short.


Continued on next post


I decided to hard wire my new connectors in. I can tell you that the wire color coding is a match for my 1991 burban. It was an easy plug and play. Tan for low beams and green for high beams.


TIP: All blue connectors are for low beam wiring and all black connectors are for high beam wiring.


Take the new connectors that came with your lights and crimp them onto the existing factory wiring harness. These will connect to your new LMC harness and will provide the on/off signal for the new relays. This after some red butt connectors and heat shrink tubing.


I use Dielectric grease on all my electrical connections. Helps keep contact and keeps moisture out. Dont spend the $4 bucks on the small permatex tube you get from an auto parts store, go to a hardware store (for me it was ACE) and spend $6 bucks on this large tube.


This seems to be a nice spot to mount the relays. I pre drilled two small holes then used two 1/4 sheet metal screws. They are clean and out of the way yet easily accessible.


End results

This was before


This was after


Final Thoughts

First off you DO NOT have to order bulbs with these headlights. Bulbs already come with them. It does not say that in the catalog so I have a spare set of bulbs.

This was a really simple project that netted some huge results. The wire gauge on the new harness is ample and plenty of length (without getting crazy) to reach even across a FS chevy engine compartment.

The connectors are so so copies of Weatherpack connectors and seem a little loose at times. Using the dielectric grease helped make a solid connection and to an extent stiffened up the connections as well.

I do wish they had used regular Bosch style relays instead of these "other" style ones.

The garage door light test does not do this upgrade any justice. the amount of light on the road is just massive compared to stock

All in all a great upgrade for a fare price.


I thought about this upgrade but never past that. Think I'll do some intro web shopping this evening! Great write-up with results. If you don't mind post up a pic of how the new headlights look in the day (not on, just how the new housings look) :ylsmoke:


Bigassgas Explorer
Nice write up Pack Mule!

I've been happy with the LMC full 12V headlight harness on my K10 so I ordered up another and installed one my Polar Bear Burb last fall as well. The kit works wonders to brighten up the headlights on old rides. On my burb I did a few things a little different.

The first was to strip off the cheap ugly yellow loom that LMC used on their harness then added OEM quality black split loom. The black split loom makes the harness look more natural and much less noticeable under the hood. Also gives it a bit more protection over the yellow LMC stuff.

I also used different headlight lenses as I not a fan of the LMC plastic toyish looking headlights. I found these glass ones that darn near spot on to the original headlamps. Only a hand full of vehicles use the small 92 mm x 150 mm H4703 headlights (low beam) H4701 (high beam) in the late 80's and early 90's leaving us with very little options in the aftermarket as far as lenses. Luckily I found these glass 92 mm x 150 mm lenses at eurolamps.com. Did I mention these are glass, not plastic? These are the eurolamps.com lenses with 9005 bulbs in the low beam and HID in the hi beam position. My only concern with these lenses is they are not stamped with a DOT label, which probably means they are not DOT compliant. Probably not an issue until someone pulls you over to tell you it is.

What I really like about the glass eurolamps.com lenses is they look almost spot on for the OEM headlights.

This dealeo is the HID module for the left highbeam headlight. I originally had the HIDs on the low beam position but poe-poe pulled me over early one morning on my way to the airport to tell me that my headlights were a blinding hazard. Luckily he didn't bother looking at the lenses to see they are not DOT labeled. No ticket, just a friendly warning. Being it was 3 AM he probably just was looking for an excuse to pull me over looking for drunks on the road. So, with that experience I decided to try moving the HID's to the highbeam position as highbeam is where you really need major light anyway. The HID's work great in the highbeam position but they do not always work. Sometimes only one comes on, sometimes both, sometimes the left, sometimes the right. I noticed they were doing that when in the lowbeam position as well. HID's are just hype.... I think I will just remove the HID all together.

So outside of the HID highbeam BS I am really happy with the results :elkgrin:

Any for those with older round eyed rigs, it is the same process but using LMC's single headlight harness. I did the same thing on the '78 K10 by stripping away LMC's cheap yellow looming and replacing it with OEM quality black split loom, glass lenses and 9005 bulbs (I think they are 9005's, I can't remember now).

Autopal lenses. Autopal is a big home, commercial and automotive lighting supplier based in India. These are not DOT stamped either :(

I used the wire covers on the new Autopal lights as one of the older lenses in the truck got broke on the Toroweep trail. I figured the little wire covers can't hurt any. This broken lense is not an Autopal. I think it was an older LMC lens before they went to all plastic.
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I've done this same upgrade with excellent results. Second best low buck for big results mod you can do on an old truck. Hard to out do 1 buck pex for old strikers mod as #1.

LMC got me on the extra bulbs too so at least your not alone. I have spares in the go box for field repairs now though.
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Expedition Leader
Thanks for the heads up PMA. Very descriptive write up.How much did the whole kit cost from LMC? This looks like an upgrade I need to do on my Yukon....:ylsmoke:


Headlights were $34 each x4 (bulb included)
Harness was $30

I dont know if they offer it for a Yukon. I think you already have the newer style halogen lights.