Quick Wiring Question

[hcmini1989 16]

right i was wiring a fan up in work on a customers car .the car used a switched earth on the fan orginaly .so it had 12v positive feed going to the fan all the time this was ok .but wouldnt work due to the earth or the fan switch being duff.so i wired in a switch .i cut the lead going to earth coming away from the fan put it to a relay then to a new clean ground .

 

then i wired a switch to the relay so it would switch the earth .is this right

 

as i was made to re do it as my boss reckons it was wrong he says the live should always be switched .why? as he couldnt explain he just knew.i would have thought it would`nt matter

 

only asking as ive wired most of the stuff up on my pug with swiched earths such as injectors etc. as per megasquirt wiring diagram

 

any help much apreciated

[welshpug 1,666]

its only the injectors and coil pack that use a switched earth on a 205 AFAIK, everything else has a switched live.

 

depends what the car you were working on was though, I know many Japanese vehicles work backwards.

[hcmini1989 16]

daihatsu hi jet .my real question is .is there any special reason for switching earth or switching live .ive done a search on the interweb but cant seem to find anything.