D*@3n!* turn signal switch!

[69RavenConv 286]

Washed and polished the 'Stang for a little 4th of July cruise today, checked the brakes and lights,  and all systems were go - until I get to the end of my driveway. My wife goes "the steering column is smoking!" At least I was still home so I didn't have to deal with traffic without signals. I'm convinced the Scott Drake unit is crap and I'm not thrilled about dropping another $80 on a new one. This is the 3rd switch I've needed in the last 8 years!

I see NPD has one by an unnamed vendor who is not Scott Drake. It's $30 more but if I never have to replace it again it's worth it.

CJ Pony Parts also has a house brand that's a little cheaper but I suspect it's just a re-branded Scott Drake.

Anybody use either of these alternates? Any other suggestions?

Thanks

[Midlife 814]

Be sure to put black electrical tape on the back side of the TS switch to cover the rivet heads, as they can short out against the steering column, which is chassis ground.

[69RavenConv 286]

Good advice Midlife and I honestly don't remember if I did that the last time I replaced the switch but I will this time for sure. What is odd is that it has worked flawlessly for about 4 years and I exercised all the signals prior to departing; they worked, then failed . I'm an electrical engineer so I should know what I'm doing (insert laugh track). I'll pull it apart tomorrow and see what smoked.

[Midlife 814]

Being an electrical engineer, you know exactly how randomly the smoke jeannie can escape the wiring: always at the most imoportune time.

[Ridge Runner 1,112]

Mustangs can take up smoking wires at any time . I drove my 66 fast back for several years with out a problem ,one day it decided that pretty pink wire in the dash looked better black ,i still have a scar on my hand where i reached under the dash and ripped it out still smoking 

[Mach1 Driver 560]

Is the failure mode the rivets melting into the plastic? If so, are you still running 1157 bulbs? Of course its worse if its a Shelby with all the tail lights. Some of those guys are lucky to get a year or two out of the switch. You can lessen the load considerably by switching to LEDs, and have less likelihood that the little rivets in the switch will heat-up and melt into the plastic.

[69RavenConv 286]

No, it doesn't appear to be an overload/melting problem, although I still run the incandescent 1157  bulbs on the 4 corners (lots of LEDs elsewhere). There appears to be a slight discoloration under the turn signal stalk so I'm thinking my pre-flight checkout may have been aggressive enough to move a rivet too close to ground. I did not have any insulation there but I will on the new install. I've got a new one on order from NPD but of course I missed all the 4th of July sale prices :)

[69RavenConv 286]

May not be the switch after all. Put the new one in and still having trouble. Deduced that the right rear brake light/flasher filament is a problem. Step on the brake (or activate the flasher) and there appears to be excessive current flowing through that conductor, which is routed through the turn signal switch as we know. More to come as I troubleshoot. 

On the bright side, I got to take my steering wheel off and remove my radio, heater controls and flashers looking for problems. Probably shouldn't have washed the car; everything worked great while it was dirty.

[Brian Conway 264]

Thanks for that bit of wisdom.    Brian

[RPM 1,190]

The wiser guys on Mustangsteve.com use an OEM nos switch they find on ebay. Expensive, but worth it they say.

[Mach1 Driver 560]

 

1 hour ago, RPM said:

The wiser guys on Mustangsteve.com use an OEM nos switch they find on ebay. Expensive, but worth it they say.

I wasn't aware they had a forum- until you got me looking around. I guess that's where you were hanging around for the last week, after Randy crashed this site. We all know he's guilty.

[RPM 1,190]

Ya, like this forum, is got a bunch of friendly knowledgeable guys. I think I found it  ~8 years ago when I was searching for brake info. 

[69RavenConv 286]

Update for those following along at home.

After taking time off to tend to a flooded basement and all the joy that goes with it, I've got time to revisit the Mustang again. Systematically troubleshooting, I've found out that headlights, taillights, parking and side marker lights all work. Same for interior and dash lights, wipers and radio. Car starts and runs fine.

Backup lights and right rear flasher/brake do NOT work. Emergency flashers did not work but discovered fuse #7 was blown - replaced it and flashers came back except right rear. Swapped flasher wires in turn signal connector and problem moved to left rear. Seems to vindicate wiring to tail lights. 

Determined with a meter that backup light switch is closing properly with shifter in Reverse. 12V is present in underhood connector with key on, yet lights don't illuminate. Seems like a clue. There's no obvious connection between BU lights and brake light but something's goofy...

Ran out of time but will continue troubleshooting as time allows.

Special thanks to Mach 1 Driver for the Real Schematic. So much nicer than that awful 2-page wiring mess that Ford gave us. 

 

[Mach1 Driver 560]

You are welcome, but I kinda did it out of necessity. My wire diagram came with the shop manual when I bought the car  50+ years ago, and that thing has over 30 pages. I could never figure out anything. Glad it helped. 

[Brian Conway 264]

Don't recall where I got this so can't verify the accuracy ?  Can anyone verify this schematic ?   The schematic has proven inaccurate and has been removed.  Brian

 

[Mach1 Driver 560]

Both 2 & 4 can't be right- there is only one temp gauge and sensor wire. If that is for a non-tach car, then look at my document on this site

 

[Midlife 814]

Pin 4 should be red/white

[Brian Conway 264]

Thanks fellas.  It seems the schematic I posted is inaccurate and I will taking it down.  Brian

[69RavenConv 286]

Ok, backup lights actually work - 4-pin firewall connector wasn't fully seated after troubleshooting.

Right rear brake/flasher filament problem points to turn signal switch since swapping left and right wires in the connector moves the problem from one side to the other. Bought some new pins, a pin pusher and crimper. Plan on removing the pins from the mating connector to buzz, inspect, and repair as needed. Still have the old switch to use as a mule also.  I will figure this out before the snow flies :)

If anyone is interested (and so I can remember, too):

Male pins (TE AMP 61116-1)

Female pins (TE AMP 61314-1)

Pusher  (don't worry about it being a GM tool, it works great for the Mate-n-Lok style pins. Cheap on eBay. Midlife says the innards from a BIC pen work, too)

Crimper (any Mate-n-Lok compatible 18 ga. to 24 ga. crimper should work)

[69RavenConv 286]

I also found this at the local big box store. Way more convenient for covering the rivets on the turn signal switch than trying to get tape to stay put. Lifetime supply, too

 

[Midlife 814]

13 hours ago, 69RavenConv said:

Ok, backup lights actually work - 4-pin firewall connector wasn't fully seated after troubleshooting.

Right rear brake/flasher filament problem points to turn signal switch since swapping left and right wires in the connector moves the problem from one side to the other. Bought some new pins, a pin pusher and crimper. Plan on removing the pins from the mating connector to buzz, inspect, and repair as needed. Still have the old switch to use as a mule also.  I will figure this out before the snow flies :)

If anyone is interested (and so I can remember, too):

Male pins (TE AMP 61116-1)

Female pins (TE AMP 61314-1)

Pusher  (don't worry about it being a GM tool, it works great for the Mate-n-Lok style pins. Cheap on eBay. Midlife says the innards from a BIC pen work, too)

Crimper (any Mate-n-Lok compatible 18 ga. to 24 ga. crimper should work)

Ummm...those are the smaller pins.  I believe you want the TE AMP A1421-ND  and A1420-ND

[69RavenConv 286]

20 hours ago, Midlife said:

Ummm...those are the smaller pins.  I believe you want the TE AMP A1421-ND  and A1420-ND

Thanks, wouldn't be the first time I wasted money on a near miss :)

Glad I posted the part number although it occurs to me I should have asked first. Hmmm.

[edit:] I pulled the data sheets, the pins I specified are for 18-24 ga wire; the ones Midlife listed will take 14-20 ga. wire. Otherwise they're the same length and diameter.

So mine are ok for the 18 ga. wires in the harness; Midlife's are ok for all the wires, so those are the parts to buy.

 

 

[69RavenConv 286]

For those of you playing along at home, I finally got the car back on the road. I spent the winter tearing down the dash, the wheel, and going through the trunk inspecting all the wiring I could. I never found an identifiable defect. An ohmmeter confirmed the turn signal switch went bad. The new part I replaced it with was also bad (uh-oh, bad harness, short, etc, right? None was found).

Replaced the Scott Drake replacement with a Shee-Mar I found on Rock Auto (I honestly don't know if one is better than the other)

Everything now works, keeping my fingers crossed.

Well, one thing doesn't work. The moron wannabe mechanic working on the repair (me) broke the horn button. so now I have no horn and it looks like the only option is a new steering wheel. anyone got a red 2-spoke they wanna sell cheap?

 

[Boss429Dreamer 18]

NPD? They show as out of stock but NC has one? Repop so quality questionable.

[aslanefe 333]

On 5/8/2022 at 12:08 PM, 69RavenConv said:

For those of you playing along at home, I finally got the car back on the road. I spent the winter tearing down the dash, the wheel, and going through the trunk inspecting all the wiring I could. I never found an identifiable defect. An ohmmeter confirmed the turn signal switch went bad. The new part I replaced it with was also bad (uh-oh, bad harness, short, etc, right? None was found).

Replaced the Scott Drake replacement with a Shee-Mar I found on Rock Auto (I honestly don't know if one is better than the other)

Everything now works, keeping my fingers crossed.

Well, one thing doesn't work. The moron wannabe mechanic working on the repair (me) broke the horn button. so now I have no horn and it looks like the only option is a new steering wheel. anyone got a red 2-spoke they wanna sell cheap?

I don't have 69 with two spoke wheel to examine, but I think it can be fixed. If you can post photos of the broken tab and the other side of the wheel where the tab was, may be we can figure out how to fix it. I have an idea but need more photos to see if it will work.