p-cardriver

For the Trailex 7541 the correct bulb is 1157, but the 2057 is a heavy duty version and lasts much longer. It should be obvious but the bulbs only go in one way. If they don't seat, don't force them - just take out, rotate 180 degrees and try again.
LED lights apparently cause some cars to think the trailer lights are out. I've seen suggestions to use resistors and other rigging to fool the car's system - seems like more things that can go wrong in the world of trailer wiring to me. But it would be GREAT to have sealed LED lights and never have to worry about that component again!
Radio Shack sells electronics cleaner spray which is great for cleaning the contacts. There is also a contact gel (like vaseline) but on our trailer it oozed enough to short the bulb/socket so I'm not a fan. Point is, do something to clean the contacts. At least once each year.
Check the wires for pinch points and reinforce with electrical tape and/or flexy conduit (whatever you call that stuff). Don't seal the conduit or you'll trap water inside - its there for wear protection, not waterproofing. If your wiring is a mess, consider buying some good quality, outdoor (sun exposure) wire and rewiring. Its not that hard. Solder the connections to avoid future failures (well, to delay them).

Bill Verburg

I did all that, the VOM says that the correct voltage is at the corrects nodes inside the socket, the issue is that a known good bulb when correctly inserted in the socket only makes contact at the 1 node for the running lights, the other 1157(thanks for the 2057 info, didn't know that) contact point apparently doesn't make contact,

I've cleaned the contacts w/ Wurth contact cleaner and mechanically and applied dielectric gel, still no joy. I'll make another attempt to r&r it today but suspect a new light is in the cards. are these generally available? or do I need to contact Trailex?

Has anyone converted to leds on these? New seems to come w/ them,

p-cardriver

That's tough to diagnose - is one node in either the socket or on the bulb sticking up just enough to keep the other from making contact? If you've got voltage at the socket and the bulb is known good, I don't know where to send you.
I was in mine yesterday because of the diaelectric gel shorting things. Cleaned it up with some alcohol but that bulb still wouldn't fire so I replaced it and all was good.

As far as replacements go, I don't think Trailex makes anything - just final assembly. So you should be able to find that assembly (or comparable) at a trailer supply store, marine store, or on line. Or from Trailex. I don't know if you can replace one side with LED and not the other - just not smart about that.

Post what you find as it will help the rest of us eventually.

Bill Verburg

Thanks for the tips, It is so frustrating because the VOM is showing the correct V at both socket nodes for some reason contact isn't mad at the one while being made at the other, maybe the spring loaded bottom is cocked or the node is eroded too much.

ground is also good that was the first thing I cleaned and reseated. All the lights except the one filament (right stop/turn) work

going to dive back in now

Sean F

Bill - while you're in there, take a good look at all the wiring.

kurt M

Be sure to have the lights OFF when you do this or you will short the light circ.

post of the day!

Voltage does not mean there is enough amps. You might have a bad conector that lets the low draw VOM read 12V but when the higher draw bulb is in place the bad conector keeps the curent too low to light the bulb. Get a bulb and socket with probes type tester and see if the tester lights. You might just have a bad $.06 crimp type Y conector. They are famous for this.

Bill Verburg

Thank you all for constructive help!!

For future reference;
My Trailex CT-7541 uses Dry Launch SP8 R and SP8 L lights

the whole light, inner & outer is available singly or as a pair and the inners are also available singly they are ~$23/ ea complete unit

mine needed 'replacement bulb slide holder for SP8 - right side' $13 at a local trailer supply

led replacements are also available, for mine I would need a light box 5 7/8"W x 3 1.2"H x 2 1/8"D, the closest match I found was Optronics TLL36RK 7 7/8"W x 3 1/4"H x 2 7/8"D, these will stick out too far to the sides for my taste/comfort

I'll keep looking, leds are the way to go

Bill Verburg

Optronics also has a 6 1/16"W x 3 5/8" H x 2 1/4"D led light set.
TLL56RK ~$65

They say it is for trailers under 80" wide but I don't think that matters as the difference between over & under 80" is just the redundant running light on the over 80" lights, the over 80 incandescent just have the normal 1157/2157/3157 bulb + a mini redundant running light so that you can't lose all the light at a corner at once