Turn signal cancelling cam help

[landy]

I bought a cancelling cam and horn contact kit from LMC for a '72, but the cam looks different than in the LMC catalog parts diagram. According to the diagram, the cam should have a little slot near the top that keeps the horn contact pin in place with the aid of a sleeve (don't know the correct name of the sleeve part) that locks into the slot. Also, the diagram shows the larger end of the contact pin going into the cam head first, but on mine the pin head is too large. My repair manual doesn't have any detailed pics. Anybody else had this problem? Maybe LMC sent me the wrong part?

Here's a link to the parts in question (#9 and #11).

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=127

Thanks!

[JimKshortstep4x4]

When compared to an original cancelling cam the picture is incorrect. On an original cam the spring goes in first then the horn brush, large end first, then there is a little barrel shaped plastic ring that snaps into the tube which holds the assembly together. The horn brush goes through the plastic retaining ring and the spring puts pressure on brush to hold it against the horn switch.

Jim

[FLcustom10]

I had to use a dremel tool to trim the head down some. Spring, then contact (head first), then plastic piece. Also - in my collection of parts I had 2 different size horn brush contacts , the shorter one worked. I'm not sure if LMC sent me one that was too long or not. I think I had to trim the plastic piece a little bit also but not too much. Now where would the challenge be if things just worked like they are supposed to???

[pritch]

Probably the only thing you need to change out is the 2 little coily springs.

[landy]

So assuming the LMC diagram is incorrect and it goes together per Jim's description, how does the barrel shaped plastic ring keep the pin inside of the cam cylinder? Seems that there needs to be slot in the cam cylinder for the barrel shaped plastic ring to lock into (I think that's what is shown on the LMC diagram).

Thanks!

[Classic Bowties]

Originally Posted by landy

So assuming the LMC diagram is incorrect and it goes together per Jim's description, how does the barrel shaped plastic ring keep the pin inside of the cam cylinder? Seems that there needs to be slot in the cam cylinder for the barrel shaped plastic ring to lock into (I think that's what is shown on the LMC diagram).

Thanks!

The LMC diagram is not like OE, Jim has it right in said order and the piece that he refers to as "little barrel shaped plastic ring" does just press into the tube part of the cam and keeps everything in place. Mel

I can get a setup out and get a picture if you need one yet.

[Classic Bowties]

Ok, I just went and took some pictures so lets see if this can get ya going in the right direction. As I had said above the LMC diagram is not like OE and also has the order of parts pictured wrong from factory OE. You never said if you were working on a tilt or standard column and they are different so I have pictured both OE types along with the OE contact kit, (also listed for any others checking this out) for tilt applications use P/N 399294 and for non-tilt standard columns use P/N 3902190, both use the same contact kit. See pics and note that there are NO notches or catches of any sort on these GM pieces holding the contact assembly in place, the small plastic retainer bushing just presses in and stays put. The last close up picture shows the clear order of the contact kit as it should be installed into the cam. Good luck, Mel.

[landy]

Yeah, a pic would be helpful. The plastic barrel shaped ring that came in the LMC kit has tabs on the side, which would fit nicely into a slot in the tube part of the cam - that is, if there was a slot in the tube.

Thanks!

[Classic Bowties]

Originally Posted by landy

Yeah, a pic would be helpful.

Are they not showing up for you, there were four pics posted a few minutes ago? Mel

[MikeyMan]

Mel,
Awesome pics and description!

I recently had to figure this out myself. I have a tilt (not original, maybe later) and replaced the turn signal switch because of a busted off hazard switch. The horn didn't work because there was no contact kit in the cancelling cam. I do have the black cam that goes with the tilt. I bought some used parts from a board member, and pulled the pin, barrel, & spring from a (white) non-tilt cam. The pieces did press right into my tilt cam. I added a dab of epoxy around the "barrel" so it wouldn't pop out. Everything seems fine, though I haven't installed the steering wheel because of other work in progress.

Mel, do you (or anyone) know the part number for the coil spring that goes under/inside the black tilt cancelling cam? This coil spring was missing in my tilt column, and will be required to make the contacts work properly. Apparently, there is no coil spring for a (white) non-tilt cam, only the (black) tilt cam.

[landy]

Thanks for the pics. Yeah, looks a little different than my kit from LMC. Yours doesn't have any tabs on the side of the short barrell shaped sleeve, but mine does. Also, the larger end of the pin is too large of a diameter to fit head first into the cam cylinder.

Guess I'll have to modify these parts to make them work, or buy an original setup.

Thanks!

[michael bustamante]

Classic bowties, im at this stage in my column rebuild also, so thank you for showing "proper procedure" looks like ill be going oe also

[Classic Bowties]

Originally Posted by MikeyMan

Mel,
Awesome pics and description!

Originally Posted by landy

Thanks for the pics.

Originally Posted by michael bustamante

thank you for showing "proper procedure"

No problem guys, pictures always work better than an explanation and they just took a few minutes to do and if I had more free time on my hands, I woulda/coulda/shoulda done this three days ago when this cam question post first popped up.

Originally Posted by MikeyMan

Mel, do you (or anyone) know the part number for the coil spring that goes under/inside the black tilt cancelling cam? This coil spring was missing in my tilt column, and will be required to make the contacts work properly. Apparently, there is no coil spring for a (white) non-tilt cam, only the (black) tilt cam.

Yes, you are correct on the no spring needed on the standard/non-tilt 190 cancel cam, it goes all the way down the inner shaft and into the upper bearing and helps center everything up. The 294 tilt only cancel cam can be found molded in both black & white and it does use a spring underneath the cam, this tilt only application spring GM P/N 3900514 has been discoed by GM for a few years now and are tough to get ahold of and not reproed as of yet to my knowledge. I use to sell my used tilt cam springs but then soon realized, that when I actually needed them for my own stuff or column builds I was having to get into my NOS stock to replace them, I could part with a few of the OE GM NOS 514 tilt cam springs for around $30. ea. shipped USPS first class in a padded mailer. Let me know, Mel.

[MikeyMan]

"Yes, you are correct on the no spring needed on the standard/non-tilt 190 cancel cam, it goes all the way down the inner shaft and into the upper bearing and helps center everything up. The 294 tilt only cancel cam can be found molded in both black & white and it does use a spring underneath the cam, this tilt only application spring GM P/N 3900514 has been discoed by GM for a few years now and are tough to get ahold of and not reproed as of yet to my knowledge. I use to sell my used tilt cam springs but then soon realized, that when I actually needed them for my own stuff or column builds I was having to get into my NOS stock to replace them, I could part with a few of the OE GM NOS 514 tilt cam springs for around $30. ea. shipped USPS first class in a padded mailer. Let me know, Mel. "

Mel,
Thanks again for the GREAT information!

I have a complete original tilt still in my wrecked '71 Cheyenne, that's how I discovered the inner spring. I'll use that spring to match up something similar to put in the daily driver '72 I'm currently working on.
Thanks for the offer on the NOS, if I can't make anything else work I'll drop you a PM.

[landy]

So in putting this stuff back together, I thought I should verify that the horn works. I applied a 12 volt source directly to the horn and it works, but I'm unclear on some of the horn parts inside the steering column.

On the turn signal switch, there's a copper colored barrel shaped pin that can be pushed in. I'm assuming that when the horn button is pushed, it pushes the horn contacts into this little barrel pin, which should then send current to the horn. Is that correct?

When I push in the barrel shaped pin, the horn doesn't activate, but maybe it needs to be grounded?

In the LMC catalog, the copper colored barrel shaped pin is part of the turn signal switch. The pin can barely be made out in attached link from the LMC catalog. It's part no. 26 (w/o tilt).

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=155

Thanks!

[MikeyMan]

You can test the horn by grounding the copper colored barrel shaped pin that can be pushed in. Just take a screwdriver and make contact with the barrel to the metal on the side of the steering column. Grounding it completes the circuit, you should hear the horn relay "click" and then power is sent to the horn(s) via the green wire near drivers side core support.

That copper barrel on the turn signal switch passes the connection to the cancelling cam, then that spring and pin contact in the cam passes it through the steering wheel where it gets grounded when you push in the horn button.

At least you know your horn works. On mine, the relay was clicking but both my horns were bad. I just installed new horns.

Sometimes if the turn signal switch is bad or grounding out, someone may pull the plug to the horn relay to stop the horn from sounding.

So to test, ground the copper barrel, the relay should click, and you should have power to your horn.

[gmc 2500 4x4]

thanx mel, i did find that all three items are available now.

[NorthernMatthew]

Great thread and I need help with my horn as well. Thanks everyone.

[cpnbnanamn]

I apparently have a thing for resurrecting old threads...
I have a '67 w/o tilt, and was finely putting on my new steering wheel tonight.. it appears I have the wrong contact pin and spring for the canceling cam. Where is the best place to get the correct one?
NM.. Ordering from Southern Kentucky Classics....

[duke10]

I am having the same problem. Where is the best place to order these parts?
Horn contact kit and cancelling cam for 72 non tilt.
Thanks in advance for any help.

[LockDoc]

Originally Posted by duke10

I am having the same problem. Where is the best place to order these parts?
Horn contact kit and cancelling cam for 72 non tilt.
Thanks in advance for any help.

I would try GMCPauls

https://gmcpauls.com/

Very knowledgeable and quality parts. Don't hesitate to give them a call if you have any questions.

LockDoc