Flasher units

[juddy]

Please can someone explain why theres a 3 pin and 4 pin version.

[Homestar]

There are a few different units 2, 3 and 4 pin.

2 pin units just have a supply going in and the other pin goes to the indicators.

3 pin units are basically the same, but have a pin out for an indicator lamp on the dash or the switch to be connected to it.

4 pin units are generally the same as the 3 pin units, but with an earth wire connected as well - usually for the electronics in them, but I think there are several different versions especially for newer cars.

For a series vehicle, the 3 pin unit is the go.

Cheers - Gav

[juddy]

Thanks Gav....

Mines got a 4 pin heavy duty one.... its ex army so thinking thats why.

[bee utey]

Euro spec flasher cans are usually marked:

49 for +12V input, fused
49a for switch and lights output
31 for earth
C for indicator globe
C2 for trailer indicator globe.

So you can use 3,4,or 5 pin electronic flashers so long as the pins are connected the right way around. I often replace old thermo element flasher cans by fitting up the required earth lead for terminal 31. It helps the stability of flash rates no end. I got sick of old fashioned flasher cans including the replacement Tridon electronic 2 and 3 pin types. You also get the fast flash mode if either a front or rear globe goes bung.

Yesterday I fitted a 5 pin RRC flasher can to a '66 Mustang by adding just the one earth wire and ignoring both the C terminals. The change is totally reversible for purists.