I have a 2005 Peterbilt 330. Single axle tractor. I have no trailer brake lights. I have brake lights on the tractor. I have turn signals on both tractor and trailer. Right and left turnsignals work also 4 way flashers work on both tractor and trailer. Brake lights do work on tractor. In the plug i have power when turn signals are on. No power when brake lights are on. Can you tell me where to look for a problem. Also all fuses are good. Tested them with a trst light.
Checked brake switch on air line. Both tractor and trailer have power when brakes applied. Wire #227 has no brake power but the other turn signal wire does
Hi I'm Wayne I will help you with this Good afternoon, Ok you have power to the brake light switch, just nothing at the pig tail1st go to back of cab, (inside), where pig tail gets hooked up check the Red wire there for power, if yes, bad cordif no , then go to under dash where the harness runs to back of cab check in there for loose ,rubbed,worn wire
The plug for the trailer has power for turn signals. Both right and left turn signals work at the plug and on the trailer. Brake lights only work on the tractor. The wiring all looks like new. No cracks, rub marks, or signs of corrosion. I checked power where wires run throught the firewall. Wire 227 has power when turn signal is on. But no power when brake like is called for.
Relist: Inaccurate answer.
let me see if i can help as per Mr wtolkson you need to verify if power for the brake lights is coming out of the pigtail put something heavy on the brake pedal and check for light at the pigtail
if you have power to the trailer then you have a problem in the trailer wiring either in the receptacle or in the wiring back to the trailer brake light or the light itself
A couple of questions. Do you use this trailer all the time? Do you have access to another trailer? Might help you decide if this is a tractor or a trailer problem.
i re read your initial problem so the problem is in the trailer. you will have to unbolt the trailer receptacle and then with it out whit acess to the wiring hook up the pigtail and see if power is getting through the circuit breaker for the brake lights if the cb and the wiring or ok then try jumping from the turn signals to the brake light and see if the brake lights flash if nothing happens then you will have to finde the harness connection box under the rear of the trailer and find the red brake wire connection and check for volts or test light there if you dont then the trailer harness has a broken wire somewhere along it if there is power then check the brake light assembly
note if you blow a fuse when you try to jump the turn signals to brake then you have a shorted wire in the trailer harnes
Problem is with the tractor. Trailer lights all work properly on my other truck. No power to lights in the plug on tractor when brake lights are on. When turn signals are on power in the plug for lights is normal. I have a problem with the brakes getting power out o the tractor to the plug for the trailer.
have you tried using a different pigtail to see if power is getting out of the tractor cab if that doesn't solve it you need to check the air brake switches in the engine compartment to be sure power is going thru the switches if there is power then it has to be in the wiring from the brake pedal or the junction box in the back of the cab
brakes need to be engaged to check brake air switch
, Your advice did not help me at all. I already checked the trailer. All is good on it. I do not have bad connections. The turn signal and brake lughts are on the same light bulb/connector in plug. I do not have brake lights to the trailer. The tractor does have brake lights aorking. The problem is in the cab. But I cNnot find where or what the problem is.
i am sorry i was not able to help you unfortunately i do not have access to a wiring diagram for your truck i will unlock and let another expert help you again sorry for the inconvience
sir i have done a little research and have 2 sites that will give you more info on this subject
hope this will help you good luck
The truck still has no lights. Your answers were no help. I need specific information for my truck wiring. A 2005 Peterbilt 330 single axle.
Hi my name is XXX. X will try to help. the trailer receptacle wiring harness should connect to a terminal strip inside the cab behind either the passenger or drivers seat possibly under a cover. Find this terminal strip ( It connects the tractor lights to the trailer harness) . Have someone work the brake with full air pressure, turns, etc and take note of their location on the strip. If you have brake light power at the strip and "going out" to the trailer receptacle harness, then check for brake light power at the trailer receptacle. If there is no power, then take apart the receptacle and inspect the wiring going into the receptacle ( Either broken wiring in the harness or to the receptacle).Make sure all connections are tight and free from corrosion. Use 7 wire shielded trailer cable sold by the foot @ most Napa stores.... etc.. that sell heavy truck parts. I hope this helps. Let me know if you need further assistance. Thanks for using JA
The 7 wire harness runs underthe cab to the firewall. At the firewall it goes into a plug throughPTL! Jack is doing great. In fact, surgeon may be sending him home today bypassing his stay in the nursing home. Not out of the woods yet so we appreciate ur continued prayers. Rehab will be slow. He can walk about 15 feet with a walker and aid. the firewall. Once inside the cab the wires become part of a wrap of wires all the same color but with each wire is numbered. I have turn signals on the trailer so that rules out bad connection. I am not getting brake lights but have turn signals. I have tested brake light senders off the airline in cab. Both tractor and trailer senders put power out to lights. Somewhere or somehow the single power wire to the brake lights are split and sent each right and left turn/brake light on trailer. As far as I can tell, that is where my problem is. I do not know where/what to look at or test to figure next step in repair.
Your directional switch on your column is where that split occurs between the turns and your stop lamps. Test your directional switch. Let me know if you need further assistance.
I replaced the tuen signal switch assembly. OEM from Peterbilt $135.00 plus tax. It did not solve my problem. Still do not have brake lights on the trailer. But turnsignals do work. Truck has both brake lights and turn signal. This problem is making me nuts. I called Peterbilt service for help. I have to call next week to talk to their wiring electrical tech.
Daniel will get back to you on this