I have a 97 Lariat that the headlights will not turn off. The only way i can get them to turn off is to disconnect the neg. batt. cable. When its running the lights are on and the high beam indicator is lit on the insturment panel. I was wondreing if anybody knew what was causing this? thanks

 

Probably, the MFS has failed so that the flash-to-pass circuit is remaining closed.

Pulling fuse F16 in the cabin fuse box should kill the high-beams.

Steve

 

Steve, I went and pulled fuse 16, that didnt kill them, I also pulled 26 & 28 for the low beams, left and right, and they still stay on!

 

If your truck has DRL, pull fuse F9 under the hood and/or fuse F5 under the dash.

Other than that, you'll need to identify any recent work or mods.

Something is cross-feeding the high beam circuit.

Steve

 

Ok pulling the f9 under the hood made them go off, what does this mean?? I havent made any mod,s or done any work on the truck in quite awhile. I have used the auto control for a long time now. The other day after coming home from work I went outside for something and noticed they hadnt turned off. Steve thanks again for your help. mike

 

sounds like your gonna have to replace the switch assembly. i recommend getting the part from rockauto.com.


if that looks like it then itll be $138.79 US + ship and that is the most expensive part in that category. cant post a direct link but itll be under electrical switch and relay, then headlight switch.

 

Ive taken the switch assembly out, its disconected, and the lights still stay on unless i take the F9 fuse under the hood out or i have to take the neg. batt. cable off. I dont get it????

 

Again, ASSUMING you have DRL, (you never acknowledged whether or not you do), the DRL module has probably failed.

Again, if present, unplug it.

Fuse F9 powers the DRL and fog light circuit, both of which are not critical to vehicle operation.

Steve

 

Steve sorry about that, i'm not sure, i forgot to ask you what DRL was?

 

I think it means daylight running lights/lamps. Basically, during the day, the headlights are on, but at a lower output. I think they are required in Canada.

EDIT: Linky

 

Those Canadians and their DRL's!

 

nope, doesnt have DRL then, if it means daylight running lights.

 

Are you sure? Nothing other than a faulty DRL module (except a wiring harness that is shorting the high beam circuit to the F9 circuit) makes any sense.

While DRL was mandatory on Canadian vehicles, it was still used on some US-market trucks as an option.

Crawl under the front driver's bumper and look up. If you have a DRL module, you will see it attached to the body just behind where the fog light is (or would be if it were so equipped). If you see only an eight pin connector with nothing in it, then your truck does not have DRL. If you do have a module there, unplug it and you'll likely find that your high beam problem has disappeared.

if you don't have DRL or fogs (or have fogs but don't care), just leave the fuse from the F9 position in the glovebox.

Let us know what you find.

Steve

 

ok I found what i think is the DRL module you were speaking of steve, when i looked up under the bumper i saw a three wire conection for the fog light, and just above that a box with an 8 wire conector. i'll un plug it tomorrow and see what happpens. Question for ya tho, is the dial for "auto" setting for the head lights run through/to this DRL module?