Backup Alarm that Can Plug into 4-Way Trailer Connector

Updated 10/22/2025 | Published 09/23/2025

Products Featured in This Question

Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End

(103)

$17.61

Light-Duty to Medium-Duty Back-Up Alarm with Wire Leads - 12-24 Volts - Less than 0.3 Amp - 97 dB

(13)

$33.56

Question:

I need a backup alarm which activates When I put my car in reverse and plugs into my trailer lights flat 4 .

asked by: Craig S

Expert Reply:

Hey Craig, the issue with a backup alarm that plugs into a 4-way is that 4-ways do not carry a reverse light circuit so there would be no way to activate the alarm at the right time. You would need to tie into the reverse light circuit somehow and best way to do that would be to convert your 4-way to a 5-way with the # C57187 which you would then tap into the vehicle reverse light circuit to get what you'd need for the alarm and then use an alert like the part # PK41820 wired to that circuit.

If you were wanting to wire the alarm to a 5-way that you'd plug in when needed you'd need to wire it to the part # HM47910 and then you'd be set.

expert reply by: Jameson C

Jameson C.

10/22/2025

Hey Craig, how did things go after converting your 4-way to a 5-way for the backup alarm setup? Your results could really help others trying to get their alarm to trigger when reversing.