Towing Relays | Flasher Monitors | Details
The most common type of device fitted to cars when they are wired for towing is a flasher monitor. The function of a flasher monitor is to provide a warning, visible or audible, that the indicator lights of a towed trailer are working or not working.
Some flasher monitors are built into switching relays (e.g. Smart Bypass relays) and some simply monitor the working of the trailer indicators. Most flasher monitors fit in the boot but some fit in the front, under the dash. These types are described in full on the pages that follow.
Boot-fitting monitors
The most common is the simple boot-fitted audible monitor. The other common type is the Smart Bypass relay described in the section on Bypass Relays. Front fitting flasher monitors are less common than they used to be.
Front-fitting monitors
Front monitors are likely to be fitted under the dashboards of vehicles, monitoring current as it enters or leaves the vehicle's flasher control circuits. These circuits are usually incorporated in a self-contained flasher relay but many vehicles have the flash rate controlled by circuitry in a larger control board, with simple switching relays working as slaves" to switch the current.
Most monitors that check the current in or out of the flasher control circuits are installed by cutting the appropriate wire to or from the relay or to the flasher switch and wiring the monitor in line. As cars increasingly use printed circuit boards to carry current where previously wire harnesses were used, finding an appropriate wire to cut has become increasingly difficult. Plug-in monitors make it easy when flasher relays are readily accessible.
The "Clone" 3 to 4 pin flasher adapter makes it easy to attach a monitoring device to the original flasher relay and just plug it back in.
See Flasher Monitors for full range of relays and fitting details.