P2 Factory trailer light harness 30664652 , trailer module

Volvos4me · Post by **Volvos4me** » 23 Apr 2019, 14:21

Can anybody tell me where the connectors are when installing a factory trailer light harness? I think I found one on the rear fuse block at least the connector fit. But there are two others on the harness and a ground that I’m not sure about. Can anybody help me out with this?

Volvos4me · Post by **Volvos4me** » 23 Apr 2019, 14:32

It’s a 2006 XC70

Post by **kranz** » 23 Apr 2019, 16:02

In addition to the wiring harness, VOLVO 2005-2008 V70 wagons & variants require a trailer module (part number 30664652). The extra connectors on your harness plug in to the module. It is my understanding that this trailer lighting feature might not be plug & play and may require a visit to the dealer to enable it and make it operational. Perhaps others may know for certain.

Volvos4me · Post by **Volvos4me** » 23 Apr 2019, 16:55

Thanks very much for the information. The picture you posted looks like it would accommodate at least one of the plugs I didn’t know what to do with. I may just call the dealer and see what they would charge for the box and anything else needed.

Post by **abscate** » 24 Apr 2019, 05:24

Added part number, edited title for search

April 2019. Not available new but lots on webs at $40-60 used

Volvos4me · Post by **Volvos4me** » 24 Apr 2019, 06:14

Thanks!

Post by **abscate** » 05 Jul 2020, 11:40

kranz wrote: ↑23 Apr 2019, 16:02 In addition to the wiring harness, VOLVO 2005-2008 V70 wagons & variants require a trailer module (part number 30664652). The extra connectors on your harness plug in to the module. It is my understanding that this trailer lighting feature might not be plug & play and may require a visit to the dealer to enable it and make it operational. Perhaps others may know for certain.

IMG_2448.JPG

IMG_2452.JPG

VIDA software load definitely required for this controller

Post by **erikv11** » 16 Mar 2022, 13:19

Bump with some questions re trailer wiring on an 07 XC70 ...

1. Is this module 30664652 really required to make the factory harness 30664651 work at all with trailer lights? For example the module may be for towing-related features (transmission, braking responses etc) beyond just lighting. But I dunno!

2. Can I make this module 30664652 work using VIDA in the driveway or does that require a dealer visit or other connection to the mothership?

3. What workaround options have others used for a generic harness, cut into wires (eek) or tap into the plug or ... ?

Links for convenience:
https://www.fcpeuro.com/products/volvo- ... e-30664974
https://www.fcpeuro.com/products/tow-hi ... 0-30664651

Post by **br0dy519** » 16 Mar 2022, 14:55

Can you use a generic 4-way and plug in through the factory harness? Works perfectly for me on my XC. And at a cost of about $15

This is assuming you aren’t using a trailer that requires a brake controller. If that is the case I have nothing of value to offer as advice and shall see myself out of this thread

Post by **erikv11** » 17 Mar 2022, 11:03

Thanks, hmmm maybe I could.

For P2 cars up to 04 like yours, the Volvo harness does not use the module 30664974. It just wires directly from the socket connecter to the trailer wires (e.g. https://www.fcpeuro.com/products/volvo- ... o-30681980 and a 7-to-4 converter). So I'm not sure the signal at the socket will work with the Curt boxes.

That Curt 56146 is out of production but 56496 is described as an upgrade replacement (e.g. https://www.etrailer.com/Wiring/Curt/C56496.html). Since my usage will be infrequent I could live with running it out the tailgate like in your video and using splice connectors.

So it looks like this Curt box brings in external power to run the trailer and then uses the signals from the car socket as triggers not as power sources, to eliminate any extra current draw and keep the bulb warning circuits happy. Makes sense it would work and maybe does some of what module 30664974 does.

These run $32 but that's without a fused power wire so for like $45 all in after picking up small installation parts I might give it a try. I'll see about wiring into the plug though if I can, instead of using splice connectors.

EDIT: OK eTrailer actually "confirms" fitment the Curt 56496 for an 07 XC70, they bundle it with a test light and inline fuse holder into their $140 (!!) kit https://www.etrailer.com/Trailer-Wiring ... =200763467. That gives me more confidence it will work fine.