Electrical issue w/headlights & brake lights

Joined
Jul 26, 2012
Messages
25
Location
San Diego
So here is the issue thats driving me crazy.

Symptoms:

1. When I have my head lights turn ON for night driving my rear brake lights stay continuously on regardless if i press the brake pedal or not.
2. When I have my headlights OFF and press the brake my fog lights light up and my clock dims. BUT the Brakes light work fine..

I have been running HID on the front for last 4 years with no issues, also I have LED lights on the rear ( brakes, reverse, and turn signals) I swapped the relay on the headlight to adjust the resistance on the HID headlights thinking it might be the issue, no change. I have disconnected the headlights to test to see if it was the balast of the HID and still have the same issue. I have checked the LED rear bulbs and they seem to be working correctly. I did get a
P1520 Stop Lamp Switch Signal code on my OBD2 reader.

Car Electrical is my weakness and need some advise from the Pro's. Where do I start to get this resolved ?

Thanks to all the Mudders that share the wealth of knowledge.
 

Tedward

95 LC
SILVER Star
Joined
Feb 2, 2015
Messages
939
Location
Cleveland OH
I have no wealth of knowledge. However, weird electronic things, exposed wires and/or bad grounds seem to hang out together.
 
Joined
Dec 3, 2015
Messages
849
Location
morro bay calif
Start with the stop lamp switch, if that dose not help start looking for worn or bare wires. I would start in the back around the tail light as that were you have stop and running light wires run together. good luck
 
Joined
Jul 26, 2012
Messages
25
Location
San Diego
Thanks for the replies, I changed the stop light switch and the problem continued. I will have to start with the back lights and check all the wires to see any suspicious grounds.
 
Last edited:
Joined
Nov 16, 2016
Messages
12
Location
Littleton colorado
Did you ever figure out the issue because I am running into the same thing and was thinking about getting a brake light flasher from Amazon to flash the brakes as I push the pedal down I know it's not a complete fix but it warns people that I'm stopping
 
Joined
Apr 4, 2013
Messages
2,281
Location
Springfield, OR
Check the tow wiring at the tow hitch for abrasion, loose wires etc...then open up the rear quarter panels and look for the same. Often times the trailer wiring is just spliced into the tail light wiring and the splices combined with years of vibration can cut wiring in half or just wear through in spots and short. If you don't find anything in the rear then run the same inspection for wear and loose/ damaged wires at the headlights. Lastly I would check the wiring under the dash. Especially if there was ever a half as$ed stereo installation done involving butt connectors, spade terminals or wiring nuts.
 
Joined
Nov 16, 2016
Messages
12
Location
Littleton colorado
I have finally resolved my issue with my brake lights always staying on. The P.O had some work done, aftermarket tail lights installed and replaced and one of the light bulbs were inadvertently switched from a dual filament that is required on the brake lights to a single. Super easy mistake I'm sure just one headache down. Make sure all your dual filament plugs have the correct 1157 bulb in them.
 
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