Please help with headlight problem

[kahoona]

Hi
I have a problem with my 2002 Coachmen Mirada. It is on a 2001 F53 chassis. The low beams blink off every 2 seconds constantly. In addition to that the low beams come on when the high beams are turned on. They are not supposed to. The highs do not come on when the lows are turned on so it is not a crossed wire between the two. The headlamp pod has separate bulbs for high, low and daylight bulbs. This may not have anything to do with it but at the time when this started the bulb for one DRL blew and I did replace it.
I replaced the multi-function switch. Checked fuses. Checked relays. I pulled one headlight pod and checked it over but saw no problem with it. Having the wiring in those looms makes it hard to check. Where do I start? Are there traditional problem areas?
Any help or suggestions would be appreciated.

[marty1300]

I had a similar issue with my mustang GT, when the driving lights were on the circuit would over heat- causing headlamps to go out. Ford used wire gauge that was too small they would overheat. Had to rewire from switch to colum with larger gauge wire.

[MEXICOWANDERER]

Even though the headlight switch is "supposed to" remain unloaded via the use of relays, any load greater than 8 amperes has caused earlier Ford headlamp switches to fault. I cannot believe they have not cured this issue. Chevrolet, and Dodge switches are immune. Not only did headlamps flicker (cycle) they would fail entirely, circuit breaker fashion. I used to cure this problem by installing Tyco relays (Bosch) fused for 20 amps.

This issue used to drive electrical shops mad, so don't feel lonely 🙂

Believe it or not, tail lamp, marker lamp issues caused the headlamp beams to go psycho. The cure? Relays for everything. Alternate brand switches were as hopeless as Motorcraft switches.

[kahoona]

MrWizard wrote:
grounds are the common suspect for many wiring problems

BUT when power blinks on / off at at regular timing intervals
i start looking for overload conditions on that circuit
do the DRLs stay on when the low beams come on ?
are they on the same fuse/reset breaker ?
if the answer to either is yes, then i would remove that new DRL bulb
and test the lights again, see if the problem changes

Thanks. I will keep overloads in mind. I'll see if they go out. I believe they should. The problem was there when I noticed the DRL was out and exists with the DRL removed.

[kahoona]

MEXICOWANDERER wrote:
Ford has had chronic headlight switch problems since the 1970's.

Since then Ford has utilized RELAYS in the power circuit, but problems continue in the control switching circuit. If your control is on a turn signal stalk look for switch control problems at the switch itself. Yes it means pulling off the steering wheel.

My thoughts exactly so I did replace the multi-function switch on the steering column.

[muzzledan]

sounds like a chassis ground problem. check the ground from the battery to the body and from the engine to the body of the RV.
I am willing to bet you have a u-joint going out as well.

[MEXICOWANDERER]

Ford has had chronic headlight switch problems since the 1970's.

Since then Ford has utilized RELAYS in the power circuit, but problems continue in the control switching circuit. If your control is on a turn signal stalk look for switch control problems at the switch itself. Yes it means pulling off the steering wheel.

[MrWizard]

grounds are the common suspect for many wiring problems

BUT when power blinks on / off at at regular timing intervals
i start looking for overload conditions on that circuit
do the DRLs stay on when the low beams come on ?
are they on the same fuse/reset breaker ?
if the answer to either is yes, then i would remove that new DRL bulb
and test the lights again, see if the problem changes

[beemerphile1]

kahoona wrote:
Hi
I have a problem with my 2002 Coachmen Mirada. It is on a 2001 F53 chassis. The low beams blink off every 2 seconds constantly. In addition to that the low beams come on when the high beams are turned on. They are not supposed to. The highs do not come on when the lows are turned on so it is not a crossed wire between the two. The headlamp pod has separate bulbs for high, low and daylight bulbs. This may not have anything to do with it but at the time when this started the bulb for one DRL blew and I did replace it.
I replaced the multi-function switch. Checked fuses. Checked relays. I pulled one headlight pod and checked it over but saw no problem with it. Having the wiring in those looms makes it hard to check. Where do I start? Are there traditional problem areas?
Any help or suggestions would be appreciated.

The part in bold most likely contains your answer. Whenever a problem arises, go back to the last thing done previously.

Wrong lamp? Inserted wrong? Defective lamp?

[kahoona]

Gdetrailer wrote:


Check the ground wires going to the headlight bulbs, the grounds may be bad feeding voltage back to the other bulbs (or filaments).. You should find one single wire at each socket that does not go into the wire loom, follow it and it should terminate under a bolt 6"-12" from the bulb socket.. Remove the bolt and clean any corrosion from the wire lug and the bolt.

Blinking bulbs can be caused by too high of a wattage (IE high power bulbs) that the vehicle was not designed for.. Typically headlight bulb circuits use auto reset breakers instead of fuses..

Overloading the circuit with higher wattage bulbs will trip the breaker, the breaker interrupts the current and the breaker cools and resets. Lather, rinse and repeat.

I think you have the answer there. The bulbs are original. I will look for that ground. The ground wires are brown and there are three of them per side on the inside of the fixture. I will find where they come out of the plug and trace it. If I can't find where they connect would it be OK to ground them to the chassis myself?

Would a cracked wire or corroded connection have the same effect as an overload? I understand the cycling breaker and I am sure that that is what is happening although I can't locate one. I'll check for ground first and get back. One thing at a time for me.
Thanks

[kahoona]

TakingThe5th wrote:
I don't know your rig but I wonder if the problem could be a defective bulb, old or new. I've had bulb filaments break and re-weld themselves in odd ways. Check your bulbs.

Thanks for this. I see that getting to those bulbs will mean removing the entire assembly and possibly pulling the lenses to get to them and they are(Coachmen sometimes did not plan well.) I will do that as soon as I can. In the meanwhile I unplugged each headlamp pod in turn and the other one continued to act up so I suspect it is further up the wires.

[John_Burke]

Sounds like a ground in the low beam circuit. Headlights have a circuit breaker in the switch (or in the circuit) as a safety feature so you do not drive down the road with a burnt fuse and no lights. You may hear a click under the drivers console also, the breaker tripping and resetting.
First unplug low beam bulbs, one at a time, turn the lights on and check. Could be a bulb filament broken and shorting to the ground side. If that does not work, check around the low beam bulbs for bare/shorted wires. Then start working your way back towards the firewall, pay close attention where ever the wire goes thru the body or other parts of the R/V.

[TakingThe5th]

I don't know your rig but I wonder if the problem could be a defective bulb, old or new. I've had bulb filaments break and re-weld themselves in odd ways. Check your bulbs.

[Gdetrailer]

kahoona wrote:
Hi
I have a problem with my 2002 Coachmen Mirada. It is on a 2001 F53 chassis. The low beams blink off every 2 seconds constantly. In addition to that the low beams come on when the high beams are turned on. They are not supposed to. The highs do not come on when the lows are turned on so it is not a crossed wire between the two. The headlamp pod has separate bulbs for high, low and daylight bulbs. This may not have anything to do with it but at the time when this started the bulb for one DRL blew and I did replace it.
I replaced the multi-function switch. Checked fuses. Checked relays. I pulled one headlight pod and checked it over but saw no problem with it. Having the wiring in those looms makes it hard to check. Where do I start? Are there traditional problem areas?
Any help or suggestions would be appreciated.

Check the ground wires going to the headlight bulbs, the grounds may be bad feeding voltage back to the other bulbs (or filaments).. You should find one single wire at each socket that does not go into the wire loom, follow it and it should terminate under a bolt 6"-12" from the bulb socket.. Remove the bolt and clean any corrosion from the wire lug and the bolt.

Blinking bulbs can be caused by too high of a wattage (IE high power bulbs) that the vehicle was not designed for.. Typically headlight bulb circuits use auto reset breakers instead of fuses..

Overloading the circuit with higher wattage bulbs will trip the breaker, the breaker interrupts the current and the breaker cools and resets. Lather, rinse and repeat.