No Signals on Wiring Harness 56042 in Highlander with Tow Prep Package
Question:
I purchased a 2010 Toyota highlander with a tow prep package. I know it has that option, it says so on the sticker and I can see the extra transmission cooler that is installed as part of that package. I purchased a 56042 wiring harness. I followed the instructions, and located the plug in for the harness, it was easy to do. After installing, I have no power coming out of the plug. the trailer lights worked on my other truck but not on my highlander, checked with meter also. I found a place on the fuse block labeled tow and installed a 10A fuse there, still no power. Any ideas on what I am missing? I know that there is another harness for vehicles without the prep package that includes a module that goes under the dash but I did not think I needed that. Mike Hahn
asked by: Mike H
Expert Reply:
Exactly what is included in a "tow package" can vary considerably. The actual parts included will be different among different vehicle brands, models and production years. You were smart to check for a missing fuse in your Highlander. I suggest another look in case there are additional fuses that are missing.
If you have a circuit tester like # PTW2993 it will be easy to test the vehicle's wiring, where the Curt harness plugs in, to see if the signals are present on the vehicle's wiring. Please have a look at the linked video that shows how to use a tester for this purpose. You'll need a helper to step on the Highlander's brake pedal and to engage its turn signals while you test the connector's various contacts.
If you do find that the vehicle's connector does carry the correct stop and turn signals then you can check that the contacts on both the vehicle and harness connectors are not bent or corroded. If all is well with the OEM connector then re-install the Curt harness and test its pins in the same way. If no signals are present on the Curt 4-pole but they ARE present on the OEM connector you tested earlier, then this tells you the harness is bad and needs to be replaced. If the OEM connector does NOT have the stop and turn signals then the issue is within the vehicle's wiring (or is due to another missing part such as another fuse) and you will want to have the vehicle wiring checked by a qualified technician.
You do still have the option of using a converter like the Tow Ready # 118449. This uses the same type of 4-pole plug in harness as the Curt does but it also includes a converter box and fuse to activate the wiring on vehicles without the tow package. As mentioned earlier on, "tow package" to your dealership may not mean a complete tow package. It sounds like the OEM equivalent converter part is missing on your Highlander so part # 118449 should do the trick. Please refer to the linked video for installation guidance.
Products Referenced in This Question
Curt T-Connector Vehicle Wiring Harness for Factory Tow Package - 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- No Converter
- Custom Fit
- 4 Flat
- CURT
more information >
Product Page this Question was Asked From
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Converter
- Custom Fit
- 4 Flat
- Tekonsha
more information >
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