Hi,
I own a 1997 F-150 and tonight my parking lights and instrument panel lights went out I checked my owners manual and examined the fuses that the books says but none were burnt..

It doesn't specifically say parking lights except on one and that fuse was ok..my friend thinks it's the light switch itself since I've always had problems with my interior light and instrument dim switch..

Please help I'm leaving for a road trip tomorrow and I need running lights..

Could it be the switch???

What about a relay???

Your help is appreciated..

 

It could be the main headlamp switch. If you want to take a probe under the dash, it should still be the Brown wire from the Main headlamp swtich.

This is the 2001 EVTM page on the STT lamps, but it should be close for you to check with.

https://www.f150online.com/galleries...028-169797.jpg

I don't have access to my EVTM until after you are gone.

 

Hey,
Thanks for the info, I'm actually not leaving until about 4am tonight so I'm going to check it out this morning, that helps a lot, I had some trouble recently with my main power wire for my trailer lights as well, maybe somehow this is related..

Your help is greatly appreciated..

Thanks

 

I just bought a 99 f150 supercab lariat 4wd and i am having the same problem. i bought a new switch, but that was not the problem. someone told me to check for a grounded wire on the trailer harness. i haven't checked yet, but i know the lights work because i can jump them out on the switch to the headlight wire and they work fine.

 

That would have been a useful piece of information. As mhilli1 posted, start with that. You can see on the page form the '01 EVTM where this branches off to the trailer tow illumination feed, so if you are having problems with your trailer tow harness, that would be the first place to start looking, rather then digging around with the switch, although checking that might not hurt, but if you roll snake eyes on the trailer tow harness.

 

well, I checked my wiring going into the switch. But I do not have a good diagram of what is what. The Haynes manual doesn't go into enough detail. I need the complete wiring diagram. I am checking Ebay for a Ford service manual, but in the meantime, does anyone know where I might find the complete diagram.

I checked my trailer harness and nothing seemed to be out of order. No fuses are blown. I am wondering now if my parking light relay is shot.

any other ideas?
Like I said, when I jump out the parking light wire onto the headlight wire, all the lights work with the headlight switch. That tells me the wiring is ok (not shorted out.) and the switch is new.

 

Q1. What part of this is not enough detail ?
https://www.f150online.com/galleries...028-169797.jpg

This is the Stop - Turn -Tail diagram direct from the Ford EVTM.
Same URL as above.

Q2. Parking Light Relay ??? Where do you get this at ?
Look at the URL posted above, there is no relay for the parking lamps on the truck.

Q3. What / Where did you check the factory harness at ?


Q4. You jumpered the Brown wire to what color wire ? Are you sure you have the headlamp wire ?

If you apply power ( or use the Tan w/ White Stripe on pin # 10 ) to the Brown wire on the main headlamp switch, pin #12, and you don't blow the fuse on the external power source ( or Fuse #6 in the BJB ), then the problem is the switch, new or not.

Power to the complete harness, and no fuse blowing, points to the switch itself. By your own statement, the factory wiring is ok, and the fuse # 6 only blows when you use the switch, then it must be the switch.

Q5. Did you actually jumper the Tan w/ White Stripe on Pin #10 to the Brown wire on Pin #12 ?

Q6. Did you do a fog lamp switch modification on the new switch ? ( don't know if you have fogs or not ).

Q7. Is the Trailer harness is the factory one ?

Q8. Do you have a brake controller installed ?
Q9. What condition does the parking lamp fuse BJB #6 actually blow under ? Just turning it on, or doing something else like needing to wait a bit, etc.

 

A1. I was hoping for a diagram showing what all of the wires going into the switch are for. I am not sure what else I might be missing.

A2. I thought the haynes manual showed a parking lamp relay. I guess I misread it.

A3. I verified that the actual wiring and lights work because I connected it to the headlight wire. My parking lights and instrument panel lights work now when I turn the switch to headlight. Everything is working now, I just do not want to leave it like this.

A4. See A3, It is the red and XXX wire, I forget now.

A5. Yes I also tried this. I got constant power to the lights.

A6. I have fogs, 1 is burnt out. I do not know what the fog lamp mod is, I just took the new switch out of the bag and plugged it in.

A7. The wiring harness seems to be factory. There are 3 plugs though. I unplugged the two parts that could be aftermarket. Not sure. The one that I unhooked was full of water inside the protective cover.

A8. I don't know what a brake controller is or looks like. If it is aftermarket, then no. Everything seems stock.

A9. None of the fuses have ever blown. This is what puzzles me. I either have 2 bad switches (1 brand new one) or there is another component that is the problem. Or the plug itself on the switch is bad. I jiggled it around trying to see if anything would come on, but no luck.

On a side note, my power locks work, but sometimes it seems like maybe they are not powerful enough. Not sure if that is related. Probably not, but I am stumped if there is no other relay in the circuit.

I would like to know what the other 10 or so wires going into the switch are for.

Thanks,
Mike

 

Mike,

The other wires are for the head lamps, and the fog lamps, nothing to do with the parking lamps that you are having problems with.

Q1. So the parking lamps, and the instrument lamps go out, but do not blow a fuse ?
- Sorry I missed that, or mroe correctly, I inferred when they stopped working, a fuse blew.
- This sounds more like a ground is having problems, but with them working fine with the wire tied to the head lamps, that is not the case ???

I asked if you did the fog lamp mod, to see if there was something else that is adding / causing the problem.

Q2. 3 Trailer plugs ??? -> That is not factory, should only be the 4 pin and 7 pin. This is good news on the what to check front. The water filled connector, can be a good source of problem.

If you drop the spare, you should see a large connector for the trailer tow lamps. This is where the plug would be converted from the std 4 pin ( non tow package ) to the 4&7 if the factory tow package is ordered on the truck.

The connector is on the driver's side, as the wiring routes along the frame rail. This should be within 3' of the 4 & 7 pin connectors.

disco of this connector will only leave the wiring along the frame rail, towards the central junction box ( the relays and fuses ), I seem to recall it does not have another connector in it, until it is in the kick panel,

The reason I say to lower the spare, is it is much easier to get to, with the spare down.

The brake controller would be in the cab of the truck, and have a non Ford name on it, connected to the pig tail under the dash.
The pigtail connector is here ( this is a '04+ dash picture, but it is the same place ) :


Like I said, I inferred that you were blowing fuses, my mistake. You never said this in any post. Combination of tracking too many threads, and reading too fast I would say.

With the ACTUAL synptoms being paid attention to now, I would say there is more diagnoses required, before I can say 100% it is the switch. Still might be, but I can't be so sure now that I am payign attention to the information posted.

The other pins on the main headlamp switch are for Auto Lamps ( if installed ), hedlamps, fog lamps. You have a few power in and out, along with the Autolamp wires. I don't have a complete pinout for just the switch handy, it woudl be spread over 6 cells in the EVTM ( headlamps w/ Flash to Pass circuit, autolamps, parking lamps, fog lamps, instrument cluster illumination, courtsey interior lamps. )

Try unplugging the large connector up under the rear of the truck, remove the jumper to the headlamps, and see if the parking lamps stay on.

If not, we are going to need to seperate the instrument panel illumination from the circuit next. This should just be removing the fuse #18 / 5 AMP, but I don't know what else is on there at the moment, I have not looked into it. The other option is to unplug the dimmer, but this leaves a bit more on the system wire wise.

Good luck, thanks for the reply, and correcting my assumptions.

steve

 

Wow Steve, thanks for the detailed reply. I will drop the spare in the morning and unplug the connector. Then try pulling that fuse. I will let you know what happens.

Thinking about it, I would guess the trailer wiring as well as the whole circuit is fine because it is working now off of the headlight power wire. It seems that, for whatever reason, the parking lamp power supply is not there/energized. That is why I replaced the switch. I am very confused at this point. I was hoping there was a second power supply wire to the parking lamps or a relay that was bad.

cliff notes: I will try the suggestions, I just think the circuit is not the problem, but the "power supply" is the problem. Does this make sense?


I really appreciate the time you have taken already to help me with my problem.

Thanks,
Mike

 

If you want to check it, you can do that, prior to the other suggestions.

You said the fuse was good, and when you jumpered the Tan w/ White Stripe to the Brown wire, the lights worked.

The Tan w/ White stripe, circuit # 195 is the output of fuse #6, 15A for the parking lamps.

Once again, I am assuming ( bad thing ) that it was ok, due to jumpering it.

Prior to any of the other items, take a meter, to a known good ground, and probe pin # 10 which should be the output of fuse #6. This is hot at all times, so no need to have the truck in the assy or run postion to test it.

Try that, before taking what seems like 2 weeks to lower the spare

 

I did this and I have juice to it. That has to mean my new switch is bad also, right? or maybe the plug...

 

Ok, so that assumption was good.
I would not think there is a problem with the plug, but it could be. Considering this happened prior to you taking it apart to replace the switch, I wound not think so.

Could be the new switch. Nothing says that a tech at the dealership did not put it in working on another problem. Take it back out, and put it back on the shelf. They are not imune to making bad parts some times. This is why electrical items are not returnable, once the package is opened, at least for you and me.

Back to trying the connector at the rear, to remove the trailer tow plugs from the equation.

EDIT : Found a picture of the trailer tow harness connector location.

 

thanks for the pic. I didn't get to check it out today. try tomorrow.