Turn signal malfunction

[_91wagonguy_]

Hey, I have a 1999 Ford Explorer Limited 5.0L AWD.

When I use the right (passenger) side turn signal It causes all (3) of my rear stop lights to flash with the Amber turn signal. I've unplugged the connecters for the rear bottom stoplights on both sides to test and for some reason the turn signal power is being sent to the all the stoplights through the (green wire) and not sure if its a short or the multifunction switch.

This malfunction only happens when I use the right turn signal and I've checked the trailer wiring and its fine.


Thanks.

 

[_91wagonguy_]

Hey, I have a 1999 Ford Explorer Limited 5.0L AWD.

When I use the right (passenger) side turn signal It causes all (3) of my rear stop lights to flash with the Amber turn signal. I've unplugged the connecters for the rear bottom stoplights on both sides to test and for some reason the turn signal power is being sent to the all the stoplights through the (green wire) and not sure if its a short or the multifunction switch.

This malfunction only happens when I use the right turn signal and I've checked the trailer wiring and its fine.


Thanks.

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Here's a vidia of what's going on. (I have strobe tail lights) but that's not the problem.

{Sorry for the crap quality}

 

[rasouth]

There are quite a few articles in this forum that talk about the same problem. You can check them out in the search or similar threads section. As for the MFS it should not control your brake lights but sometimes different lights share the same ground wire or relay. Does your blinker come on when you brake or just the brake lights come on when you use turn signal? I would start by checking fuses, relays, bulbs...

 

[_91wagonguy_]

There are quite a few articles in this forum that talk about the same problem. You can check them out in the search or similar threads section. As for the MFS it should not control your brake lights but sometimes different lights share the same ground wire or relay. Does your blinker come on when you brake or just the brake lights come on when you use turn signal? I would start by checking fuses, relays, bulbs...

I didn't see any articles with the exact same problem and checked everything-( fuses, relays, bulbs) and my brake lights (stoplights) come on when I use turn signal. Other then that problem everything else working normal.

 

[DR98FL]

I am intrigued. I have a 99 Ex factory wiring manual to guide me.

I need to know about the strobe tail lights, because I don't know anything about them.

How long have you owned the Ex and when did this problem start?

I am wondering about the installation of the strobe tail lights causing the issue.

Was your Ex an emergency vehicle?

What exactly did you do to determine that the strobe tail lights are not the problem, as you stated in your post.

Fill me in and I 'll do what I can.

DR

 

[J_C]

I suspect you have a wiring fault, that somewhere between the right turn signal bulb and the shared ground, there's a break in the wire and this is causing it to backfeed through one brake light then finding ground through the others. Wiring diagram attached.

 

[_91wagonguy_]

I am intrigued. I have a 99 Ex factory wiring manual to guide me.

I need to know about the strobe tail lights, because I don't know anything about them.

How long have you owned the Ex and when did this problem start?

I am wondering about the installation of the strobe tail lights causing the issue.

Was your Ex an emergency vehicle?

What exactly did you do to determine that the strobe tail lights are not the problem, as you stated in your post.

Fill me in and I 'll do what I can.

DR

I've already had the strobe LED bulbs in a while before this problem, and this only started happening a couple days ago, but I did go get an emissions test and right after that is when I discovered that the lights were having this problem. (I seriously doubt that the emissions test had any thing to do with this.)

Also I determined that the tail lights weren't the issue by disconnecting them at the connecter and using a test light at the plug and the (third) stoplight was still doing it despite me unplugging the two bottom lights. (third brake light is untouched with the incandescent bulb)

 

[donalds]

 

[J_C]

Use multimeter (with lead extensions as needed), check continuity between all points and resistance to ground at points on wiring diagram, and in the power path, voltage relative to chassis ground.

 

[_91wagonguy_]

Problem solved!

I removed the multifunction switch and took it apart and inspected the whole thing, Fiddle Faddled with some of the contact points that were close together. One of the wire prongs must have been touching one another. Not completely sure which one it was but I put it back together, reconnected it and no more funky blinking of the tail lights.

I'm probably going to get a new multifunction switch anyway, its the original one and it could possibly happen again.

Thanks for the help!
I appreciate it fellas.

 

[J_C]

I can't see what you can see, but when I refurb'd my MFS, I cleaned old hardened grease out, polished up the contacts, relubed with dielectric grease (which is obviously not what they used from the factory or else it would not have hardened, nor have been soluble in gasoline and petroleum solvent based brasso polish I used to clean it), and then it was good as new, maybe better.

That's cleaning the base of it, if you take apart the stalk end, there is a loaded spring for the detents on the wiper interval that may fly out, so be ready to capture it.

 

[DR98FL]

Great news. First thanks for reporting back your success. This helps everyone on the forum when it's done.

Second, I am the original owner 98 Ex 133k miles. Near the 100k mile mark. I had turn signal trouble (buzzing noise) no signal. I did exactly what J_C posted to the letter above. I didn't get the switch piece that comes out of the stalk set correctly. Tore down set it correctly. Still working to this day original motorcraft piece 133k miles.

Give it a try save some cash!

 

[Larry Compton]

Hey, I have a 1999 Ford Explorer Limited 5.0L AWD.

When I use the right (passenger) side turn signal It causes all (3) of my rear stop lights to flash with the Amber turn signal. I've unplugged the connecters for the rear bottom stoplights on both sides to test and for some reason the turn signal power is being sent to the all the stoplights through the (green wire) and not sure if its a short or the multifunction switch.

This malfunction only happens when I use the right turn signal and I've checked the trailer wiring and its fine.


Thanks.

Check the ground for the right turn signal. Or the control box for the trailer lights could be internally shorted. The control box is needed because the brake and turn signal lights are separate on the vehicle and the same on the trailer. I have seen a bulb short out like that but very not likely.