Hello all! I've got a 2001 F150 Super Crew (5.4L/2v/automatic transmission) and I've got a few issues - most pressing is the front left turn signal doesn't work. Let me give yo a rundown on the symptoms & current status:

The Front right turn signal works correctly and so does the right rear.

When you hit the turn signal to the left - NOTHING happens with the front left turn signal bulb, but the left rear turn signal light flashes fast - and so does the left indicator arrow on the instrument cluster (along with the fast clicking on the dash indicating a bulb out)

I have swapped both front turn signal bulbs out and they both work in the right turn signal socket - but neither works in the left turn signal. Even got 2 new bulbs and tested with same results (ruled out the bulbs)
The right front and rear right bulbs flash normally.

When I hit the emergency flashers the front right turn signal bulb and the two rear bulbs (Both left and right) flash normally - but the front left signal bulb does nothing ??

When we arm & disarm the truck alarm on the key FOB - ALL 4 BULBS FLASH (even the front left) which I believe eliminates a ground issue because don't believe there is a separate ground for the turn signal part of the bulb and then alarm PART..

Since I'm a disabled senior, and since nothing in my life has been easy, I figured the problem would be in the hardest area for me to reach (the flasher relay under the dash). Got a new flasher relay and after changing the flasher, I still have all the same symptoms so at least I guess I've eliminated the flasher as the problem

I'm not a automotive electrician but I just got ahold of a cheapie HF multi-meter so I'm going to try and see if I get 12 volts to the socket when the signal is on? Not really sure which side is positive or negative, and I don't have the ability to pierce the wiring to see upstream from the socket if I don't see 12 volts.

Other then that - I guess I should check the Multi-Function Switch on the steering column, and the connector to it - but I'm not at all sure on what to do or how to test them (other than to look for a loose wire). My son said he would come out and help - but he's very impatient and wants to know what to check, and HOW to check it BEFORE he starts.

Any and all help and advice is welcome and appreciated. I'm sorry for being a noob, and please forgive my ignorance for asking stupid questions (trust me, if I had the money I would have already taken the truck to a mechanic and told them to fix it)

 

**Note: I just noticed that the turn signal bulb (which is a 3157 Ambar) has 2 filaments. One closest to the top of the bulb, and the other filament below it and closest to the base of the bulb. I'm assuming the bottom filament is the turn signal part of the bulb because the top filament flashes when we arm & disarm the truck alarm - if that helps diagnose the problem

 

Since you've confirmed the bulbs are not the problem, I suspect you've got a wiring problem to the turn signal filament in the left front bulb. Possibly a broken wire or a loose, corroded or broken connection, maybe at the bulb connector, which is behind the bulb socket. It should look something like this:https://www.partsgeek.com/wlgv6nx-fo...connector.html The fact that your left tail light hyperflashes tells me the truck "thinks" the turn signal filament is not passing current, which is usually due to a burned-out bulb, but a bad wiring connection will have the same symptom. You can probe the two internal positive power points in the socket with your multimeter positive probe, and your negative probe attached to a convenient ground while you have the parking lights on and the left turn signal activated. I think you'll find that one of these points has voltage and the other doesn't . The lights share a common ground, so that's not the problem. If the test works as I suspect, you'll just have to trace the wiring back from the bulb until you find the defect. I suspect the key fob lock/unlock flash uses the parking lights, not the turn signal lights.

It's also possible there is corrosion in the socket itself. You'd just have to clean that out. I strongly doubt there is a problem with the multifunction switch.

- Jack

 

Granted, my eyesight is bad, and I'm not as nimble as I used to, but I tried putting the test leads to my cheap HF meter into the turn signal socket without success. My plan was to put the leads in and find out what side or terminals feed the side of the bulb that works/flashes when you arm/disarm the truck alarm. No matter what I did - I couldn't get any indication of the 12 volts - I know I must be doing something wrong since I know the top filament WILL flash with the truck alarm being armed/disarmed. Does anyone know what terminals in the bulb socket I should be putting my leads on? (There has to be a path to the bulb somewhere in the socket, for the alarm/disarm ;pulse to light the bulb). Or is this a problem in the steering column MFS? Sorry to be such a noob but thanks for the help

 

It sounds like you were trying to put BOTH leads into the socket? Don't. Clamp the negative lead to a frame ground (unpainted metal). Then, probe the socket with the positive lead. I don't remember which terminal in the socket feeds the turn signal, but one of them will be live (I think), with the parking lights on and the left turn signal on and the other will show no voltage.

- Jack

 

Thanks. I'm hoping it's something as easy as changing a socket or pigtail

 

Well, we wiggled wires at the MFS and got the Emergency flashers to work on the front left turn signal - which I believe is the same filament that the left turn signal uses. (we also swapped the bulb & socket with the right side and it works fins (so we eliminated the socket as the problem. We removed the steering wheel clamshell and my son found a couple of loose wires. My question: what compound or whatever can we put in the connector socket to hold the wired in? (so they don't loosen up and wiggle out)? At this point I'm guessing that the wiring may be the problem and I need to know what we can use to hold the wires into the connect. I'm not sure super glue would be the answer in case we need to remove the wires later. Anyone have any ideas?

 

Good troubleshooting! Does the wire itself come out of the connector or does the internal connector come our with the wire? I believe that internal connector would be crimped on the wire, so if that's loose, you need some way to re-crimp it. But, if the connector is still attached to the wire, you just need to hold it into the larger body and glue would work. Since you have everything exposed, I don't think it would be TOO difficult to just replace that whole assembly. You can find a matching wiring harness online and then just splice the wires from it to the wires in your truck.

I wouldn't worry too much about having to remove those wires in the future. That area is supposed to outlive the truck, in terms of service life.

- Jack

 

Thanks. The wires have the metal connector on them - they just pop out of the plastic housing easy. However, my son said the wires seems tight when we plug the housing connector to the MFS. Maybe the pins on the MFS create some tension? IDK, but I think I'm gonna put on some clear silicone gasket sealer and let it dry. That should hold it.

 

This is what you need:

https://www.rockauto.com/en/catalog/...onnector,15725

You can either cut and splice, or depin the connectors and reinsert.

Tilting the steering wheel can put strain on the wires, recommend you set the wheel where you want then leave it alone.

Your old connector probably has broken tabs that retain the pins in the connector.

 

Thanks! Do you know a good wiring crimp connector kit to use?

 

GLC gave you a link to a source for a new connector assembly. That would be spliced onto the wiring to the connector you are replacing. My preference for this kind of splice is a soldered connection that is covered with shrink wrap tubing on each wire. But, insulated butt connectors will work too. You can find a crimp tool for these where you find the butt connectors.

You said though, that the internal pin or female connector was still attached to the wire. In this case I'd simply reseat them and then apply a little E6000 glue at the backside of the connector housing where the wires are inserted. E6000 is very strong and flexible and you would not be pulling those wires out of the housing in the future. It sounds to me like you don't really need a new connector assembly.

- Jack

 

The harness was just a touch too short and would get pulled tight if the column is tilted all the way down. If you tilt the steering wheel all the way up and everything works, then its usually a loose pin at the MFS