BearKiller

There's three sitting in the driveway right now and I couldn't say for sure whether the side/corner markers flash or not without going out in the rain to check.

If the side-markers do indeed flash, then things get a little more complicated.

The bright element of the front-markers would then GROUND through the side-markers, thus causing the side-markers to go out whenever the front ones flashed, and vice-versa.

Or maybe the side-markers GROUND through the bright side of the front-markers and lose this GROUND when the front ones flash, thus going out.

If this be the case, then neither would be lit at the same time; when the front marker flashes ON, the side-marker would be out, then the side-marker flashes ON and the front marker is out.

If both flash simultaneously, it gets even more complicated; I will have to go dig through my new electric books.

Of course, if the side-markers don't flash on these trucks, then none of what I just typed applies.

jimbo486

any ideas would be helpful since mine don't work at all!

BearKiller

OKAY, verified on the wife's 1991.5 :

The side-markers do indeed flash.

With the parking-lights ON, the front marker stays lit when the turn-signal is flashing, meaning the front bulb should be a double-element 1157-type bulb.

The side-marker bulb is a plain old 194-type single-element push-in bulb; it flashes ON when the front flashes OFF and vice-versa.

Does that help ??

jimbo486

are the side markers still lit when the running lights are on (even without signals flashing)? i have dual element 1157 bulbs in my parking lights.

BearKiller

YES....................................

jimbo486

that was my thinking. mine are off altogether though i'm not electrical savvy, but the first thing i think of is a bad ground.

BearKiller

Bulbs are good for sure ??


What does a test-light tell you when you probe the bulb-sockets ??

jimbo486

i haven't probed the sockets, but both sides just went out all of the sudden. i'll have to mess with it when the motors back together and things have power.

thrub

I just probed mine today and with the bulbs out the markers flashed and they lit with the clearance lamps. Looks to me like they ground through the signal/clearance lamps on the front of the truck But I can't for the life of me figure out how it all works.
My lt guage is reading lowwer every time I drive my truck. Put the battery tester on when it is running and it shows that it is charging just fine. Is my guage hooped or have I got more wiring issues?
I still can't get my RWAL light to flash me any codes. It just stays lit.

thrub

Found my problem with the marker lights. Cheap LED bulbs for front signals. They looked like the right bulbs but don't work like the right bulbs. Put new bulbs in and tried the markers and everything works like it should.

BearKiller

That was simple enough.

I am not a big fan of LEDs for marker-light applications.

They have their place where very low current draw is necessary, such as indicators that remain lit when the engine is off, or battery saving flashlights.


I am constantly running along beside or behind some big truck or other that will have a bunch of LED markers; it is a rare one that will have every one of the little "LEDs" lit.

In most cases, maybe half of the little circles will be lit; or more likely, one entire marker will be constantly flickering on and off in no particular rithym; following one of these for half the night can be quite annoying.

thrub

I thought the LEDs would lessen the load on the electrical and come across these LEDs in a discount surplus store. I would still like to switch to LEDs, so I guess I'll look for some better quallity bulbs and try them.

BearKiller

If you will put your markers either on a seperate BIG switch, or a relay, thus taking them away from the puny factory switch, you won't need the LEDs.

My truck has probably over fifty markers, the trailers have a lot more, none of which are LEDs, and all of which are double-bulb units; I seldom have to replace a bulb; and, even with the 20-plus-year-old standard-issue 1G Ford alternator, the lights are bright and all electrical functions are fine.

Simply replacing the lights with LEDs and not re-working the wimpy factory system is just a band-aid fix.



I don't think a LED bulb is going to support the side-marker blinking business as the function requires the bulb have an electrically continous element.