what the different from a cheap relay and the bosh relay

[hawkespcs]

what the different from a cheap relay and the bosh relay that TVR used. and what would you do if you find out a garage have fitted a cheap relay and caused a problem with a wiring loom.

[2Munkys]

Dunno, but I remember Mark Adams telling me that he'd had several of the various makes apart and you really do get what you pay for. Siemens spring to mind as having good quality internals and decent contact pads; some had no pads at all. I understand TVR used good stuff.

[fatjon]

Biggest trouble I have had with cheapo relays is water ingress. On a project car I used quite a few of them, they got a bit of damp in them then the contacts corroded and started to arc because of poor contact when closed and eventually burned out, some quite spectactularly with melted plastic and burned crimps and wire insulation from the heat.

[monoloco]

I'll hazard a guess that you are talking about the fuel relay with the red stripe painted across it??? These fail on a regular basis and look like a bog-standard lucas/bosch/etc relays but are anything from £12 to £20 each depending on where you try to get them, as opposed to about £4 each for a 'normal' automotive relay. If so, the answer is the 'red stripe' relay has a diode in SERIES with the coil and is there to prevent the ECU being powered up (and totally FUBAR'd) if the battery polarity is reversed. So, you can use a normal relay of the same pin-out and power rating but you'll be taking a big risk if anyone does manage to reverse the battery. Shop around though -I eventually got these for £5 each so bought half a dozen as spares -can't for the life of me remember where I got 'em though!