My 96 4x4 / 4 door Blazer project truck is proving to be a little unusual. Most of the U-Tube videos of the 96 4x4 / 4 door Blazers are not the same as mine in many ways. My blower motor is in the engine compartment and I have no DRL module. I'm not sure how much I trust the wiring diagrams I have pulled off the net either. As I look through them, I find Jeeps and Fords listed with the 96 4x4 / 4 door Blazer schematics.

My DRL issue was easy [DRL/Fog lamp] fuse. I found a great video showing how GM low beams barely reach past 15 yards and High beams light up street signs but totally miss pets and small children (because the low beams are off). The problem is noticeable in cars but much more so as the headlights get higher (as in trucks.) In this video the guy spliced the high beam power (as it comes off the dimmer) to the low beams. In effect the dimmer shuts off the low beams but the splice powers them anyway. In simpler terms, it appears that the low beams never turn off. So, just when you want a whole lot of light out front; you get it all!

My 96 has wiring for EVERTHING. Cruise control too. On top of that I have a "Code Alarm / Sure Start 433" to start it up remotely all interlaced in the harnesses adding a ton of new wire. I have to take it all apart anyway to create a "Dome Override" because the 96s didn't have them. I also want to put in LEDs as well as the new Stereo. Once I am sure what to cut and splice I plan to get it all done at once. I don't want to cut and have to repair anything I don't need to bother.

Is there perhaps an old thread regarding the Headlight "Quad Mod" on these forums somewhere? If so, a link would be appreciated. If not, I think something a step by step "how to" for this would be of great value to Blazer forum members.

 

Use the 'search' function for "quad headlight" and you'll find what you want.

 

Thank you rriddle3

The search turned up like a dozen threads. I read most with an eagerness to learn. Unfortunately, as soon as the posts mentioned "pin 85 or 87" I knew the vehicle they are referencing is newer than mine with entirely different harnesses.

I have spent hours watching U-Tube videos that are terrific at the things I want to do but not applicable for a 96 4 door 4x4. The 95, 96 and 97 seem to be wired the same. In 99 the Blower motor came inside and most of the electrical under the dash changed - mostly with the lighting.

One thread was so close to a variety of fixes with and without DRLs for years all starting at 98. But I read closer the thread started 10/2014 with a last post in 2015 I am gonna try to PM the poster. He says all his data is from an old thread by swartlkk but I don't know if it's polite to contact him about it because it may be a fragmented "re-publish."

 

I think you will need to wire in a relay to accomplish this on the older composite headlights. I would splice the relay into the wiring at the headlight.

You'll need to tap into the high beam wire (light green) to pin 86, ground to pin 85, +12V (either switched or battery) to pin 87, tan wire from chassis to pin 87A, and tan wire to low beams to pin 30. Since pin 87A is the normally closed contact, this will allow for normal operation of the low beams. When high beams are requested, the splice from the high beam wire will activate the relay and put +12V to the low beam filament.

Attached is a schematic that should apply to your truck.

 

swartlkk

Thank you so much ! I have downloaded dozens of schematics but this is the best by far.

When you say "pin 87A," and all the other pin numbers; are you referencing male spade connectors on the relay? If so, exactly what relay should I pick up?

 

Yes, referencing the pin numbers as found on the bottom of the relay. CLICK HERE for a handy guide to relays from The12Volt.com.

As far as what to get, that would depend on where you are going to place it. Behind the headlight on the inside of the radiator core support is a fairly clean and mostly dry area where you could go with a common 30A 5 pin relay that has it's own mounting. I prefer to have a connector that also has a screw hole for mounting so that the relay can be swapped without removing any screws. I have a box of these types of mounts that I purchased years ago on surplus. I wasn't able to find them on a quick glance through Amazon, but the attached picture is what I am talking about.

 

Thank you again Swartlkk

I am gonna learn what I can from that link. The image you posted looks like it is set up for male spade plugs. Is that right?

 

The image I posted will have female terminals attached to the wiring that will run out the bottom of the mount. The male terminals are part of the relay. The mounts that I have came pre-wired with ~8" of wire from each of the terminal locations in the mount.

I also have a few that just came with the appropriate female terminals to be able to attach your own wires directly without using butt connectors to your wiring and I have seen them come bare so you would need to provide the appropriate female terminals with locking tabs to keep them in the mount.

THESE RELAYS (Amazon.com link) have the mount point integrated into the body of the relay, but also come with a connector harness that has a length of wire to work with. They are rated at 40A on the normally open contacts and 30A on the normally closed which should be more than sufficient for the low beams.

You will also want to pick up a fuse holder for the +12V feed for short protection in case something happens to the wiring.

I am not advertising for Amazon, but it often is the easiest resource to get decent pictures of things. You can likely buy the same stuff from your favorite auto parts store and even walmart.

 

Thank you Swartlkk

I am kind of a "horder." As such, I have quite a collection of most things automotive. In electrical I have fuses, mini fuses and Monster fuses as well as a variety of relays. I have one that is nearly a perfect match to your example. It has no mount hole but once its running OK I will duct tape it behind the headlight.

I'm a little lost after ground to 85 and then tan wire from chassis to 87A then another tan wire to pin 30. Is there a ground [from chassis] tan wire as well as a low beam tan wire or are we splitting one wire to ground and 87A and the other to pin 30?

The 12v switched or battery should mean it will not be drawing power unless the relay is activated and I will put an inline fuse on it. I started to take out the DS headlight when these questions came up. Then I got sidetracked cannibalizing a ZR1.

 

Swartlkk

My (lack of) understanding relays is as confusing to me as chasing down a "fuseable link." For the sake of clarity: When you say tan wire from chassis to pin 87A, and tan wire to low beams to pin 30 - do you mean cut [interrupt] the tan wire from the harness and connect to 87A; then connect the remaining tan lead to the low beam to pin 30?

If so, I'm clear. Now the only remaining issue for me is where to find a reliable +12V (either switched or battery) to pin 87. When I do things like this I hate to run 10' of hot wire. Someday, somehow, it may get crushed or otherwise ground to chassis and create an issue. Or there maybe a good intentioned mechanic trying to solve another issue and cut it for lack of understanding it. If I can keep it under 18" this mod can be "compartmentalized." Can you suggest a close "hot spot?"