Side marker "lenses", what's the deal?

[dmjlambert]

I would like to ask for some guidance about my 69 CST/10 please. My goals is to get the truck mechanically sound but leave the outside as-is as much as practical (for now).

For the Texas state inspection, a mechanic who does inspections let me know all reflectors must be crack free to pass inspection, and he pointed out that mine are deteriorated and cracked with age.

When I look them up to buy some, they are called side marker lenses. I was wondering why they are called lenses instead of reflectors, so I took them off. The front one came off in 2 pieces and the inside of the holder looks like it has an indentation. The back one came off all in one piece with the holder.

What is the deal here? Are the lenses used whether or not there are lamps behind them? I'm confused by what I see offered online for replacements, because some come with a holder that has a cross-shaped hole in the back, but there is nothing that looks like it would hold a light bulb. Mine just has a round plastic surface, no hole. I also find some that look like 2 horizontal bars, with or without chrome trim, and those are quite different from what I have. So, I don't know what exactly to get. I don't know if I want to light these up, I don't have wiring that goes to the holes where they mount. At this point I would just like the truck to pass inspection so I can get it registered.

If I did get the whole assembly with the cross shaped hole, and I wanted to add a lamp to it, what sort of holder would hold itself in that cross-shaped hole? If I started out with unlit markers, would I just cover up the hole to keep water, dirt, and bugs out? Example of new one I see offered is the last picture I posted below.

[ArkansasDave69]

I was a Texas inspector for several years. If it's just a reflector I don't remember anything in the book about it. If it had a light behind it, it can not show any white light through the cracks. If it doesn't you're good to go, but it does have to be the correct color. If it's faded you might just try a colored bulb. If he didn't charge you the inspection fee like they are required, you might just try some other station

[dmjlambert]

I did not get an inspection yet, this was just a visit from a relative of a neighbor and we were talking about the truck. Perhaps he is overly meticulous and if I avoid his station I will be fine. I don't have anything I would call cracks, but he was calling them cracks. It is on the surface and I suppose I would call it aging and crazing. No white showing through from lights behind, it was only the actual reflector surface he was talking about, not the lense areas of the plastic with light bulbs behind. I have more stuff to do to fix things that are definitely broken, such as the dimmer switch, intermittent headlight switch, horn is dead, mirrors rusted off, parking brake pedal seized with rust, etc. so I will work on those things first.

[ArkansasDave69]

I would call you good on the side marker lights and let you go if it was me unless some law has changed since 2008 when I was last licensed. Good luck to ya

[dmjlambert]

Thanks very much. Perhaps that is another $100 I don't need to spend right now (4 side and 2 tail lense/reflectors). It looks cosmetic to me.

[ArkansasDave69]

You're welcome. Hope it works out for ya

[FirstOwner69]

This may answer some questions...

My 69 CST came new with markers like yours (see 1st picture below). They have a reflector at one end and a lens at the other end without a light and just a raised circular area on the back (where a light provision would be provided later on). The lens and reflector portions were, in fact, separate pieces (see picture 2). I noticed soon after I purchased the truck that other CSTs I saw had lighted deluxe side markers (those with the horizontal bars and stainless trim). Thinking I got ripped off, I contacted Chevrolet. They advised me that my truck was produced the 2nd week of December,1968, and that the lighted markers were not used until a couple weeks later. The non-CSTs got lighted standard markers like yours but they were modified to accept lights. The third picture shows the bulb holder used with lighted markers of both types. The holder is installed and turned a fraction of a turn to lock it in place.

It appears your truck was an early model year build that would have had the standard markers without lights and that the lens and reflectors on one are no longer adhered to the housing..

[mike16]

maybe hes trying to do you and others on the road a favor by being maticulous. in the aviation industry its called being safe. If he called you out on it and you went somewhere else thast your bad not his. sort it out and fix what needs fixing. He's doing his job and there are legal ethical and moral responsabilities that go along with it. New lenses cant cost that much. they look better too. cumon' now, spend a little coin on your hobby

[Gmc.guy]

My 69 has the same front reflectors. Were the rear/red lenses the same, just reflector? My bedsides were pretty wasted in that area. Wife harness was too rough to give clues too I am far from that on the truck still. This thread made me think of it again

[Nufsed]

I'll have to re-trace the research on this subject, but the issue was caused by federal regulations and lobbying to change the time frame of their implementation.
The car makers typically would implement coming changes in the model year prior to the requirement coming into effect.
FMVSS108 is the rule that required the marker lamps. At first, the proposed legislation was going to require every *car* to have SML in by Jan '68 which would've been mid-year change. The car makers were already ahead of this and adding the SMLs on cars prior, starting in mid 1967 with car production for the 1968 model year... but (if I recall correctly) the lights weren't going to be required on pickups yet. Then a bit of congress vs bureaucrat back and forth, and the proposed change was amended to lights OR reflectors for the first year (but now including trucks), THEN, 12-31-1969, lights would be required for all vehicles.
GM, in a bit of a scramble to add the trucks to the program (and still be well ahead of its implementation date), went the reflector route on trucks until 12-31-68. They had lights on all models of their cars (as far as I know) already in place for all of the 1968 models.

Another oddity is that *big* trucks (over 80" wide) were required to have the full-on lights from 1-1-1968. It actually started from the big trucks, first, then down to pass cars.

This shot below is from a report fifteen years later, evaluating the effectiveness of the rule (it was very effective)

[Already Gone]

If you don't want to buy new ones, look on the parts board here as there is always selling decent used markers for 30/40 bucks a set of 4. If you don't see any for sale put a Wanted To Buy WTB post on the parts board. You would have to pay and be a subscribing member to post in the For sale Section.

[dmjlambert]

Originally Posted by Gmc.guy

My 69 has the same front reflectors. Were the rear/red lenses the same, just reflector? My bedsides were pretty wasted in that area. Wife harness was too rough to give clues too I am far from that on the truck still. This thread made me think of it again

Yes, the front and back reflectors were the same type, just amber in the front and red in the back. So it looks like mine was made just before the lighting requirement.

Besides the reflector itself not having the bulb holder, my wiring harness does not put wires for adding a bulb near that hole on any of the 4 corners of the truck. I am not clear what sort of lighting goes there, if it is supposed to be just running lights or turn signal too.

[dmjlambert]

Originally Posted by mike16

maybe hes trying to do you and others on the road a favor by being maticulous. in the aviation industry its called being safe. If he called you out on it and you went somewhere else thast your bad not his. sort it out and fix what needs fixing. He's doing his job and there are legal ethical and moral responsabilities that go along with it. New lenses cant cost that much. they look better too. cumon' now, spend a little coin on your hobby

Yes, probably. New lenses will be about $100. A little more if I get the lenses for the front turn signal, and rear back-up lights, which don't have reflectors and are not technically needing replacement, but I probably will. I am over budget right now, and concerned.

[dmjlambert]

Originally Posted by FirstOwner69

The third picture shows the bulb holder used with lighted markers of both types. The holder is installed and turned a fraction of a turn to lock it in place.

Thanks, that is good info. If I go ahead and get the new lenses with holder and they have the cross shaped hole, where do I get the bulb holder? Is there a name for those? If I'm going to replace these reflectors I might as well just go ahead and light them up.

[old Chevy guy]

Just running lights. Easily spliced in if you had a mind to.

[dmjlambert]

Originally Posted by Nufsed

I'll have to re-trace the research on this subject, but the issue was caused by federal regulations and lobbying to change the time frame of their implementation.
...
This shot below is from a report fifteen years later, evaluating the effectiveness of the rule (it was very effective)

Thanks, that is great info.

Originally Posted by old Chevy guy

Just running lights. Easily spliced in if you had a mind to.

Thanks. Not very easy to splice if I can't figure out a bulb holder that fits the lens assembly to splice in.

[Nufsed]

There was a lot of confusion over what the final requirement would have in it and each mfr had to decide how to address it.
Chrysler took this approach

[SASROD]

Originally Posted by Gmc.guy

My 69 has the same front reflectors. Were the rear/red lenses the same, just reflector? My bedsides were pretty wasted in that area. Wife harness was too rough to give clues too I am far from that on the truck still. This thread made me think of it again

Do you have any pictures of your wife harness, and is that an option on the spid?

[FirstOwner69]

Originally Posted by dmjlambert

Besides the reflector itself not having the bulb holder, my wiring harness does not put wires for adding a bulb near that hole on any of the 4 corners of the truck. I am not clear what sort of lighting goes there, if it is supposed to be just running lights or turn signal too.

Your truck would not have the wiring provisions. When I restored my '69 a couple years ago, I stripped the needed front and rear wiring from trucks in a local junkyard. The rears were easy since all you'd need is the rear harness. I found through this process that the wiring varied a bit depending on the year. As an example, the earlier trucks lit all four markers, but the fronts did not flash with the turn signals. Later (year?), the fronts flashed. I think I got 2 different rear harnesses as well, but the functionality was the same.

Originally Posted by dmjlambert

Thanks, that is good info. If I go ahead and get the new lenses with holder and they have the cross shaped hole, where do I get the bulb holder? Is there a name for those? If I'm going to replace these reflectors I might as well just go ahead and light them up.

The bulb holders had the wires molded in. I installed deluxe markers sometime in the 80s and used holders with wires clipped off to fill the holes (as seen in my earlier post). If you can find a junkyard near you that has a couple of these trucks or vans from the from the 70s, 80s and, 90s you'll find lots of bulb holders and markers that will work. The vans up to about 1985 used the same standard and deluxe markers as our trucks. The later years used smoother markers as seen in the picture below.

[Gmc.guy]

Originally Posted by SASROD

Do you have any pictures of your wife harness, and is that an option on the spid?

Wife harness .... You know. Them hooks that go in the door frame with the heavy duty ropes.... Haha. Dang typos

[Gmc.guy]

Originally Posted by dmjlambert

Yes, the front and back reflectors were the same type, just amber in the front and red in the back. So it looks like mine was made just before the lighting requirement.

Besides the reflector itself not having the bulb holder, my wiring harness does not put wires for adding a bulb near that hole on any of the 4 corners of the truck. I am not clear what sort of lighting goes there, if it is supposed to be just running lights or turn signal too.

My whole wire harness is near perfect,I can see there wasn't anything for fronts, about afoot behind the cab it gets rough and I couldn't tell on the rear, thanks for the info. I have some old square body harness, I was planning to splice fronts on, I'll have to do the rear when I get there

[mike16]

back in the day when the lenses were unavailable or too expensive, we glued them together with model glue and sprayed them with a spray can clear coat. also spray can painted the part that mounts the bulb with chrome bumper paint. much brighter than nothing or even the white paint often used.

[70STOVEBOLT]

Does anyone know when the turn signals were implemented on the front side markers? The lights on my 70 (built 10/69) did not flash. I installed a front harness that came with my 72 cab and now the front side markers flash with the turn signals.

[dmjlambert]

Originally Posted by 70STOVEBOLT

Does anyone know when the turn signals were implemented on the front side markers? The lights on my 70 (built 10/69) did not flash. I installed a front harness that came with my 72 cab and now the front side markers flash with the turn signals.

Do the side markers flash with the turn signals and glow steady when your lights are on and you're not turning? Or are they only turn signals now and have no other light function? Do they behave differently when your headlights are off vs. on? I am trying to picture what could be done to just the wiring to make them have more than one function without a relay or something, and I can't think of a way.

Thank you folks for all the great info in this thread. I went ahead and updated my side markers and all the other lenses on my truck. I found the bulb sockets at O'Reilly Auto, so I'm going to light them up.

[dudehitt]

First post btw. Just got my 72 C10 Saturday.

It's really easy to make side markers blink even if they aren't supposed to as long as they aren't LED bulbs. Just tap into the turn signal positive wire use that to replace the negative wire of the side marker. If the headlights are on and the turn signals are off that wire will be grounded so the side markers work. When the headlights are on and the turn signal comes on you will get positive voltage on both sides of the bulb so it will go dark. When the headlights are off the positive voltage from the turn signal will go to the normally negative side of the side markers and light them up.