The trailer brakes on my 2004 Nissan Titan do not work. Where is the sub harness located?

Marvin

• 85242 Answers
• Posted on Jul 28, 2008

SOURCE: 2004 F250 No brakelights/turn lights on trailer

You will need to get a 12 volt test light and check the trailer connector for a voltage signal to the trailer, it may also have seperate fuses under the hood for the trailer lights if the system is factory installed, federal law requires the 2 systems be isolated, if there are blown fuses find the short in the trailer before replacing fuse(s), with no exceptions the short is always in the trailer. Hint, check the fuses 1st.

SOURCE: 2005 Chevy Tahoe Trailer Running Lights Out

Depending on what type of trailer you have, a blown lightbulb on one marker could kill them all (like the old Christmas light strings). Look at those, and make sure your ground is good.

SOURCE: Tailer running lighs dont work

There should be a fusible link somewhere in the wiring. That should be where the problem is at.

SOURCE: 2005 trailblazer trailer light connection

Should be in the front under the hood in the main fuse box on the left side of vehicle . look for the aux fuses for the traler plug.

SOURCE: 2004 nissan titan, shift lever

Hello gary823

Thank you for choosing fixya.com.

First things first: I suggest taking your truck to a mechanic or an auto parts store that can do a diagnostics test done. If any fuses or relays are blown, this test should bring up any codes that would indicate any type of malfunctions.

The shift lever being locked: In newer vechicles, the brake pedel, as you know must be pressed in order for the transmission to be put into gear. There should be a sensor on the transmission that runs in cahoots with the brakes. This sensor tells the computer what gear the transmission is in. It is very possible that at the last time you put the vehicle in Park, that the switch had it's final moment of ability. If the sensor is in fact useless, it may be the reason the transmission is locked into Park. It may be the reason why the brake lights aren't working; and why the brake lights fuse is blowing. Also, check all relays, (can be tested with a fuse tester) and make sure all relays are good as well. Make sure also that the light sockets for the brake lights, tail lights, back up lights, and front running and blinker lights are in good condition. One faulty socket, can cause more than one bulb to blow, or cause fuses and relays to blow as well. Follow the wiring for the brake lights for as far as you can to ensure there is no damage (melted, broken, etc.). This could also affect fuses. This truck I see is barely 5 years old, but you'd be surprised how quickly parts and wiring and such will go bad, or wear out and/or just quit working.

If the transmission sensor is not the problem, and all fuses and relays are good. tranny fluid is full, check the linkage under the truck. It may be jammed somehow, or stuck. On the transmission, where the lever inserts, there is a seal - inside that seal, there is like a gear that the lever pushes in order to shift from gear to gear etc. You may need to have that checked out to make sure it's not broken inside. If your fluid is low, or empty, you may have froze up your transmission, however, you most likely would have been seeing large amounts of fluid in the frequent places you park. Another think to check is your differentials. Make sure the fluid is full in each, as well as the seals not leaking. The seal sits just inside the inner most part of the pumpkin (differential ball) where the yoke is inserted. Maybe you have just locked up the rear driveline. Check the seal on the front end of the driveline as well, (goes into the rear of the transmission (yoke). Check your U-Joints as well, making sure they are intact, tight. It may be a good idea to have them replaced if they look supsicous in any way.

These are all the things I can think of that would make your truck be stuck in park, and make your lights not work, and blow fuses.

I sincerely hope this information is useful and aides in the successful repair of your truck. Thank you again for choosing fixya.com. Please let me know if I can be of further assistance, or if you have any more questions or concerns (comments).

Thank you again,

carsandcomps
Guru, fixya.com
Oregon