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Front turn signal question

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Steam Power

Front turn signal question

So my left front turn signal, the indicator light on the dashboard, and the light on the left fender just recently stopped working with the turn signal switch. The flashing rate has not increased any, the rear signals work just fine, and all the lights blink properly with the hazard switch.

I got to looking at this schematic: https://forum.garysgaragemahal.com/file/n77969/1985-etm-page79.jpg
And looking at it, I see an issue with the contacts in the turn switch itself could easily cause my symptoms...
However, two things confuse me in the schematic. First, I don't see the light on the side of the truck? Unless that's the "indicator light"... But it the side light is the indicator, where's the dashboard light? One or the other is missing. What is the proper name for the light on the side of the truck in the fender?

Also, the front turn flasher bulb in the schematic shows 2 elements, but only one wire feeding the bulb socket? Why are there 2 elements? Is this schematic complete or is there some other wiring diagram with a detail that was omitted from this diagram?

Since the signal stopped working all of a sudden, I wondered if one of the filaments in the bulb burned out and is causing the whole problem.

Any thoughts or advice is welcome.

1985 F-150 4x4
standard cab, long bed, 300i6, manual 3 speed

ArdWrknTrk

Re: Front turn signal question

Administrator

The EVTM reduces the diagrams to only the circuit being examined.
You see two filaments because the bulb has a dim filament for lights on (or park) and a bright filament for turn or brake.

Another 'gotcha' you have to be conscious of is that the schematics will show connectors (C123) but only the circuit in question. So C123 may be across multiple pages, and only showing one wire when in reality it may be a multiple wire connector shared by a bunch of different things.

If just one corner is out I would be swapping the bulb and checking the ground of that particular socket.

The other filament of the bulb is shown as the parking lamp under exterior lamps:

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Front turn signal question

Administrator

Right. And the light on the side of the truck is the "marker light", which shows in the schematic Jim posted. As shown it is a single-filament bulb and doesn't blink with either the turn signals or flashers.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

ArdWrknTrk

Re: Front turn signal question

Administrator

The right and left indicator lamps are in the gauge cluster.
You can get a clue of that by checking in the EVTM where the connector to it is located.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Steam Power

Re: Front turn signal question

In reply to this post by Steam Power

Well the problem is definitely in the turn signal switch. I figured it was since it was both the front turn signal light and dash indicator lamp that was not working. But by happy chance I discovered if I lift the signal switch lever ever so slightly after flipping the left blinker on, it works just fine.

Old truck stuff. :) Always some little trick you gotta know.

1985 F-150 4x4
standard cab, long bed, 300i6, manual 3 speed

Gary Lewis

Re: Front turn signal question

Administrator

Glad you found it. Are you going to replace the switch or just use the trick - until it quits working?

Gary, AKA "Gary fellow": Profile

Steam Power

Re: Front turn signal question

Since I can make the signal work, several other problems take higher priority. In my mind, this one was more operator error than defect. Sure it's not 100% perfect. But that's just one of the quirks that makes the truck "mine" by learning.

1985 F-150 4x4
standard cab, long bed, 300i6, manual 3 speed

Gary Lewis

Re: Front turn signal question

Administrator

Makes sense to me. There are always more layers of the onion to peel, and you just have to figure out which one to peel next.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Front turn signal question

Administrator

In reply to this post by Steam Power

Edit: I'm an idiot.....

At any rate I'm glad you've found the culprit.

I do believe I've seen a couple of posts to the forum regarding some brand of switch having brittle plastic.
So you should probably be careful which replacement you end up purchasing.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Steam Power

Re: Front turn signal question

Poor quality replacement parts? They wouldn't make those, would they? LOL

Seriously tho, that's just another good argument for leaving it be and living with it. It's not like it's a hardship.

On to the heater issues!

1985 F-150 4x4
standard cab, long bed, 300i6, manual 3 speed

FuzzFace2

Re: Front turn signal question

I would try a little electric contact cleaner.
Spray it up in there and move the switch back and forth.
It could have a little dirt on that set of contacts and the cleaner & moving may fix it.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

BigBrother-84

Re: Front turn signal question

Big Brother's one was so dirty that no cleaner did the job.
So I put it on the bench and carefully disassembled it, taking picture of all steps. If I remember well, I had to carefully drill one or two rivet.
Cleaned it, bit of grease and reassembled the switch.
Works like an new!

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

Gary Lewis

Re: Front turn signal question

Administrator

How 'bout posting the pics in a new thread to tell us how to do it?

Gary, AKA "Gary fellow": Profile