Please help, I am new here.

I have a 97 F-150 with factory autolamps. My autolamps quit working tonight and I can't figure it out.

I have check all fuses, I can use a test light and ground them to the green/yellow wire at both the switch and sensor. They come on.

I would like to know how to figure out if it's the switch or sensor.

Just so you know, I have a remote start connected to the brown parklight wire on the main switch, not that should have anything to with it.

Thanks in advance

 

When you say they don't work, is it they don't turn on, or they won't turn off ? I am guessing that they won't turn on.

Looking at the 2001 EVTM that I have in front of me.:

The photo cell in the Auto lamp module might be toast.

To check the switch for correct function, there should be a light green w/ red stripe wire from the main light switch, pin #7. With this should have 12V on it when the key is on, and the head lamps switch is in the autolamp position. If there is power here, the Autolamps is getting power from it, and then it comes down to the Autolamp module or the RPO relay block.

The Light Green w/ yellow stripe is the relay ground on the Autolamp module. This is under the grille on the dash if I am reading the parts locator correctly. 4 pin connector to the module, this is pin #3.

This is the output that goes to the park lamp relay and the headlamps relay in the RPO relay block. This relay then takes power from the battery junction box fuse #3 ( 30 A ) and puts power back to the other side of the headlamp switch, as if it had been turned on. This is on the pin #9 of connector C246 a Red w/ yelow stripe wire. There is also a park lamp relay with a similar function as above, different fused circuit.

If I try to describe this, the headlamp switch has a branch circuit via the Autolamp module and the RPO relay block with the switch in the autolamp position.

If you ground the pin#3 light green w/ yellow stripe on the autolamp module, and it works, then is should be a bad autolamp module. Check pw1981's post for the part number for this, it might be the same for your year truck.

If you ground the output wire from the Autolamp module and they don't turn on, then it is time to check the RPO relay block.

Un-plug the Autolamp module, and ground the light green w/ yellow stripe wire, with the Key in the run position, and make sure of what happens.

In my 2001 EVTM I don't see a light green w/ a yellow stripe on the switch, only a light green w/ red stripe, which is the power circuit from the battery junction box fuse #3 to the autolamp module when the switch is in the auto lamp position. This should have power on it, not ground. ??

The brown wire is common to the park lamps both at the switch, and at the output of the RPO relay block, and should have power to them when turned on, but this should not affect the autolamp operation as I can see it.

Remove the autolamp module and apply ground to the light green w/ yellow stripe wire and see if they come on. If so you can try to put black electrical tape over the snesor and wait 30 sec to see if ground is on that wire, but I would not hold my breath wiating for it to happen, sounds like it might be gone from what I read in my 2001 EVTM. Hope this helps, I don't have a 1997 diagram in front of me to check this against.

Good luck, let us know what happens

Steve

 

You are right, if I ground the lt. green/yellow wire the lights come on. I have done this at the autolamp switch and the sensor, both trigger the lights on.

So it appears that the switch is bad and not the sensor.

I already used the tape method and it was no go.

Thank you for your response.

 

SSCULLY IS DA MAN! (JMC is also da man though...)

LOL!

 

Which Autolamp switch ? The main head lamp switch or the RPO relay block ?

If you apply ground at the pin on the Autolamp module, and they illuminate, then the Auto lamp module is not working correctly would be my guess. Unless the Photo cell in the Auto lamp module is working correctly ( which the black electrical tape tells me it is not ) then ground will never be applied to the ground side of the coil on the relays in the RPO relay block.

With the Head lamp switch in the Autolamp position, the Light Green w/ Red stripe should have 12V on it, not ground. If you ground this, I don't know what else you are doing to the system.

Can you tell me what else you are grounding aside from the pin #3 on the Autolamp module ?
Please give the pin # and the color code ( still can't find Light Green / Yellow stripe on the head lamp switch itself, just the Light Green w/ Red stripe ).
I was of the thought that the Autolamp module n the dash was toast, not the headlamp switch ( autolamp switch ?? ).

Again I am working from 2001 EVTMs here, but it seems that the circuit is the same for both years.

Remember all the testing needs to be done with the key in the run position, any other and no telling what can happen with the testing.

 

Just wanted to update you.

You were right it was the sensor on the dash. Put a new one in and everything works.

Thanks guys, this board is great.

Chuck