i have a 98 f-150 4.2L and the problem i have is my right headlight on low beam wont come on. when i turn on the hi-beams it turns on. i used 3 different bulbs and it did the same thing. i checked every fuse and still no changed. i checked the plug and it wasn't corroded. i checked and there is no power going to the plug. i asked the dealer and the told me to changed the relays and i bought them. i replaced the ones they told me but still have the problem. so if anyone can help me i would appreciate it.

 

A little bit of clarification :

Q1. When on the low position, only the left is work on low, when on high position, both high beams work ? ( i.e. low beam never works on the right side ).

You checked the connector for corrosion.
Q2. Did you use a meter on the connector ?
2.1. This would be to check that the ground on the connector is good.
2.2. This would be with the low beams on, meter on the Dark Green w/ Orange stripe and black ( ground ).

Q3.Are there DRL or Autolamps installed ?

Q4. Which fuses did you check ?
4.1. There are a few different fuses
4.2. I would suspect the PDB fuse # 8 to work, considering the left low beam works. PDB = Power Distribution Box = Under hood.
4.3. Did you check Central Junction box fuse #26 ?
4.3.1. This feeds the right headlamp and the DRL module.
4.3.2. Central Junction box = CJB = inside pass compartment.
4.4. Central Junction box fuse #28 is the fuse for the left low beam.
4.5. Central Junction box fuse #16 seems good, with the high beams working.

Q5. What relay(s) did the dealer suggest you change ?
5.1. I don't know of a relay in the headlamps, fogs yes, DRL, no but there is the DRL circuit, and the DRL resistor.

The fuse #8 in the PDB feeds the MFS, which in turn feeds CJB fuses #26 & #28, then off to the Left and Right headlamps.

Let us know about the clarifications, so you can get on with fixing the problem.

Good Luck

 

Q1.yes on low position only the left works.

Q2.no not yet but i used a test light.
2.1 the ground is good.
2.2 i will have to look what color it was 2mrw.

Q3. i only have the basic kit on my truck. there are only headlights, running lights, tail lights, and the cab light. i dont have fog lamps.

Q4. yes i check the fuses in the cab and under the hood. i pulled every one and checked them.
4.3 yes i did and i even replaced it.
4.4,5 i checked them both and they were both good.

on the relays i can get the part numbers 2mrw and in my book it say the truck has 2 relays for the head lights. one under the hood and one in the passager compartment.

more info on the truck too its a

1998 ford f-150 short bed single cab. 2x4 stx and has a 4.2l v-6 motor. also is a stick and it has no options. its the most basic one u can get.

i will check all the stuff u asked me 2mrw afther work.

thank you for the info and i hope the info i give u is enought to answer a few of ur Qs.

 

Q1. The high beam works on the works correctly, right ?

Q2. With the test light inserted from the bulb side, I am guessing that the test light showed no power on the low beam, but on the high beam it showed power ?

Q3. DRL = Day Time Running lamps. What is the trim level, a XL ? If so, it might not have AutoLamp setting on the main headlamp switch. That is DRLs and Autolamp, not fog lamps.

Q4. When checking the fuses, did you use a test lamp or meter to see if there was power in the fuse socket #26 ? This is an internal jumper in the fuse box between both sides.

Q5. Not the part number of the relay, the relay position in the 2 fuse panels. I just downloaded the owners manual in PDF format, and looked starting on page 134 ( actually the relays start on page 138 ) and there is no note of a headlamp low beam relay. I wanted look to look again, as operationally this is how my 2001 was.

I looked in the 1998 EVTM, and the diagram also shows no relays.