Ground Problem

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Oct 28, 2024 | 09:06 PM

Sprocket118

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Cross-Country

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Ground Problem

I walked into the garage this evening and noticed my brake lights were on. They must have been on for a while because the wire connectors I pulled of the pressure switch were hot. I have previously grounded both tail/brake lights running a wire from the lights to the frame. ( I had one light that was brighter than the other.) I am now wondering where else to look? Also when I removed the tail lights from their mount the lights went out. Any suggestions are welcome.
Mike

Oct 28, 2024 | 10:32 PM

Bob Ingram

Fleet Mechanic

Joined: Jun 2020

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From: Hillsborough NJ

That doesn't sound like a ground problem. It sounds like you have voltage going to the lights, maybe through the switch, but maybe through another source.

Oct 28, 2024 | 11:00 PM

EffieTrucker

Phantom of the Phorum

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From: Kentucky

Could the pressure switch be failing? Or the brake pedal adjusted a little too tight, not allowing all of the pressure to be released?

Oct 29, 2024 | 03:40 AM

ingo

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I don´t like the pressure switches they have too many failures. I put a motorcycle brakelight switch in all my old vehicles.

Oct 29, 2024 | 05:13 AM

52 Merc

Hotshot

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From: Burbank, WA

Quote:

Originally Posted by Sprocket118

The lamps are grounded through the mount, so when you removed the lamp from the mount you ungrounded it and broke continuity, which is why the light went out. If you had power going through the switch at rest, as noted above, you either have a bad switch or have a mis-adjustment in your linkage, causing pressure at the switch which is closing the switch, sending power to the lamps.

Oct 29, 2024 | 07:07 AM

lshort

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Joined: Mar 2002

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From: Newton Illinois

do the lights go out when you remove a wire from the brake pressure switch?
also try fiddling with the turn signal switch and hazard light switch.

Oct 29, 2024 | 07:25 AM

hooler1

Fleet Mechanic

Joined: Sep 2010

Posts: 1,834

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From: Mason City, Iowa

Quote:

Originally Posted by Sprocket118

I have previously grounded both tail/brake lights running a wire from the lights to the frame. ( I had one light that was brighter than the other.)

Good move! I did that to mine too for the exact same reason. It fixed the brightness issues between the the two sides.
About the brake lights being on. I agree with the others. Its probably a bad brake light pressure switch. You could either replace it or use one if those universal mechanical ones with the little adjustable arm that rides on the outside of the brake pedal arm. If you don't want to drill some small mounting holes to the bottom of the cab to hold it over the brake pedal arm you will need to come up with some kind of bracket to bolt the bracket and switch to the frame. I did the latter on mine and it works very well.
Sorry I don't have pics for you.

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Oct 29, 2024 | 08:35 AM

Sprocket118

Thread Starter

Cross-Country

Joined: Apr 2021

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Thanks guys, I was thinking it was the switch but it is a relatively new switch. I can start there anyway and replace the switch then look more into an electrical/mechanical switch.

Oct 29, 2024 | 09:00 AM

#10

lshort

Laughing Gas

Joined: Mar 2002

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From: Newton Illinois

Quote:

Originally Posted by jniolon

The problem is with chinesium quality parts, I bet if you could find a NOS switch it would be fine.

Oct 29, 2024 | 09:19 AM

#11

bmoran4

Parts Nerd Extraordinaire

Joined: Sep 2010

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From: Western NY

Personally, I have never had an issue with the stock style brake switches in my fleet. I think most reported issues with the pressure switches are improper installation with too much torque which compromises the unit. Simply use a deep socket and don't go all HULK SMASH on it.

Oct 29, 2024 | 10:03 AM

#12

Sprocket118

Thread Starter

Cross-Country

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Thanks for the tip bmoran4

Oct 29, 2024 | 10:07 AM

#13

abe

Fleet Owner

Joined: Dec 2000

Posts: 25,403

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From: Central PA

My brake light switch failed at Truckstock as guys following can testify to. I ordered a new one from Midwest Early Ford for only $7. It works fine for now. Whenever I back into the garage I check for brake lights.

bmoran has a good suggestion about not cranking the switch too tight. That makes sense.

Oct 29, 2024 | 10:16 AM

#14

lshort

Laughing Gas

Joined: Mar 2002

Posts: 952

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From: Newton Illinois

Quote:

Originally Posted by bmoran4

I realized that the one that I had fail was not working when the cruise control would not disengage further inspection showed that it was leaking a small amount coming out of the switch end, I had similar multiple problems with a F250 cruise control switch from Orileys, a motorcraft unit solved the problem.

I assume that of all the switches available there is a range of quality but how to figure out a good one