having problem w/ 98 f-150. first truck stuck in park. figured out how to get around that (turn key 1 position, shift to neutral, start vehicle, then engage trasmisson). but no brake lights! I have turn signals, driving lights, hazards, etc in rear. I disconnected harness from brake light switch. there are 2 leads, 1 hot, 1 not. i jumped them and no brake lights. i tested the switch and it functions properly (it's reconnected now). i changed my bulbs in tail lights. I unplugged the solenoid (which is impossibly located behind/beside steering column). this allowed me to shift like an old truck (without having to brake first), but doesn't solve my lack of brake lights (i've reattached the solenoid harness to remind me of my problems).
i am putting my money on a broken wire somewhere between the brake light switch (b/c that was good) and the solenoid (i am not hearing that faint click when i step on brake). but a broken wire should work by accident some of the time (unless cut cleanly and completely). there is a green wire with red stripe leaving the brake light switch and 3 wires at the solenoid harness (1 green and maybe a smaller gauge than those at the switch and 2 others which i don't recall their colors). Ford service manager doensn't think it's the solenoid but wasn't otherwise helpful except to say, "hey, why don't you bring it in to me."
looking for some insight as to what to look for before i plunk down $65/hr for someone to perform what I already have before completing the job!

can i splice a wire from something (? brake light switch?) to something (?wire in solenoid harness?) or does that "electronic signal" get processed somewhere else first?

 

same thing happens on my work trucks go down to napa and get a breaklight switch that has always cured it for me ........ the solinoid is hooked on the cold side of the switch so no break lights no come out of park

tony

 

kickinwing;

"I disconnected harness from brake light switch. there are 2 leads, 1 hot, 1 not. i jumped them and no brake lights. i tested the switch and it functions properly (it's reconnected now). "

when you pull the harness off of the brake light switch and jump the two female connectors, wouldn't that serve the same function as the brake light switch?

 

Happened on my 97. Turned out the light green wire going to the brake switch on the pedal had broken from bending over the past ten years. This is right at the bend point. I just stripped the ends, and used a butt splice. Problem solved.

 

Did you check for power going TO the BOO switch?

If none, check F13. If blown, look for leaky cruise disconnect switch.

Does your high stop light come on but the corners don't? If so, it's usually the MFS or its connectors.

Steve

 

EsoxShop:
I tested the 2 wires at the switch. One was hot, and the other wasn't (as I would expect, normally). I stuck my tested in the "lower" connector (not hot) and depressed the brake. It became "hot". That tells me that there is power at the switch and that the brake switch functions properly. I didn't take any readings on the voltmeter, I simply used the audio function to tell me the presence/absence of current. Thank you for the suggestion...got any more?

ProjectSHO89:
1) What is BOO? If it is the brake switch, then I may have covered your suggestions in EsoxShop discussion, above.
2) F13 both looks good and tests good. Connector on Master Cylinder is clean and dry.
3) My High stop lights do not work either (cargo lights do).
Thank you for the suggestions...got any more?

 

When was the last time you checked all your brake lights. The high mount may not work because it is burned out. Lots of people never realize the bulbs are burned out till none of them work. So its possible none of the bulbs are good, or the high mount bulb is burned out and the MFS is also kaput. If you have power going to the switch and the wires are good at the switch (carefully inspect) and you jump the connector and still NO lights at all then first check the high mount for power. If good change bulb and continue diag at the MFS. If no good do circuit trace.

Likely is a broken wire though because your shift lock actuator is also not working. (assuming you have checked fuses and even have power there)

 

Sounds like an open wire (LT GRN) between the BOO (Brake On/Off) switch and splice S231. From S231, the signal is distributed to everything that you indicated was not working.

S231 is located on the Main harness, near T/O to instrument cluster.

Chances are, the open is, as already suggested, in the first couple of inches of the wire from the BOO switch.

Steve

 

HomerWinzlow: Thank you for reply. As a simple, cheap piece of mind, I changed all the brake lights ($8). I haven't looked at MFS yet, so I haven't ruled it out. I am still going to search for an open wire as that is the easiest (and least costly) to repair and I don't have to purchase an electrical part which I would not be able to return if it were not the problem. I did check my fuses and there is power at the fuses.

ProjectSHO89: Thank you for reply.
1) Will i be able to identify the splice as "splice S231" (other than being the lt green wire and to double check, Is it lt grn or lt grn/red?
2) I am not good with the acronyms...what is "T/O". Can I get at it with the plastics I already removed (bottom of steering column- off, top -still on, piece that hold brake and hood latch-off, top of dash - on, instrument cluster - on, fuse panel door - off, fuse panel inner door - off, piece behind wheel and in front of cluster - off). In other words to I have to unbolt the fuse panel - if possible.

Thanks, Dan!

 

99% of all the ones I have fixed in the past with a broken wire were right inside the connector to the brake switch and up to 4 inches up from there.

 

Had a similar problem with my 99. I had a guy pull up beside me @ a light one day and tell me I had no brake lights other than the third (high mount). Checking it out, I found that when I tilted the tilt wheel up all the way, the 2 (tail) brake lights would light. Put the tilt wheel down, they wouldnt light. The problem was the connector at the 4 way flasher (on top of the steering column) had a wire(to the brake lights) pulling out of the connector. The barb that holds the wire into the connector was'nt doing its job, and everytime I tilted the wheel down, the wire would pull out just enough to break contact. If this sounds right to you, pull the ignition switch out, pull the upper and lower shroud from column, and check the connector I mentioned. A little dab of superglue holds my wire in now, cause I could not get the barb to hold it. Hope this helps.

 

You can buy the hardshell for that connector at the dealership for about 11.00. But he said his highmount also does not illuminate nor the shift lock actuator works, so that eliminates the MFS pigtail in this instance.

 

Homerwinzlow: I carefully examined the first ~15 inches of the grn/red wire from the BOO. It is continuous. I found no breaks. I unwrapped the protective casing (not the insulation) all the way back to a huge ganglion of wire buried behind the fuse box (under the dash). I even removed the fuse box and slid it inward and downward (to keep it still connected) in order to get a better view. Everyday, it seems like I take something else off of my truck and someday I'll have to try to figure out how to piece it all together.

99FordXCab: I'll be sure to check that, but like Homer says, I don't have high mounts either.

Thanks both for the replies.
I suspect that it is "something under the dash". I was able to briefly commandier the "assistance" of my wife to look to see if I had brake lights yesterday. As I handled and jostled the first 4 inches of the 2 wires coming from the BOO, my assistant said "Yeah, you got them, no, yeah, no, can we go now?" That led me to believe that I had a broken wire. I the break was before it got bundled up with a lot of other wires because they are taped pretty good at the factory. If I were to wiggle the wire I probably would only be effecting that portion not otherwise secured (taped) further up.
I have been unable to replicate the brake lights again.
And can anybody help me with locating the items that projectSHO89 talked about in Post#8?

 

Some more information:
I don't know if this will help, but I unplugged the harness at the solenoid. There are 3 wires going into it. 1 wire was not hot and the other 2 were hot, regardless of whether the brake was depressed or not.

How should these read and what does this eliminate?

(Still I haven't actually checked volts, just the presence of current. It is kinda difficult when your half hunched up and out, underneath the dash and overweight. I have simply been using my tester audibly).

Thanx again, Dan!

 

Generally the green and red is usually good. That is the one that should have 12V from the fuse box, which you already stated was fine to the switch. You should be tracing the ground side of the circuit or load side which is the light green wire. Do you not have power from the fuse box to the switch?