pwam2006 Posted May 4, 2010 Share Posted May 4, 2010 Hi all, Am fitting a work light to the disco, 55 watt halogen. Wanting to use a spare standard discovery fog light switch to turn it on/off. Any thoughts as to whether I can run the power straight through the switch (55/12 =~ 5 amps) rather than have it switch a relay? I can't find the amp rating for the switches... Failing that anyone know if theres a way using a multimeter to work out the amp rating of something..? Though I fear its probably a case of putting amps through it until it gets hot and thats your amp rating....! Ta for any thoughts/previous expereinces/guesses Ryan Quote Link to comment Share on other sites More sharing options...
PaulMc Posted May 4, 2010 Share Posted May 4, 2010 Hi all, Am fitting a work light to the disco, 55 watt halogen. Wanting to use a spare standard discovery fog light switch to turn it on/off. Any thoughts as to whether I can run the power straight through the switch (55/12 =~ 5 amps) rather than have it switch a relay? I can't find the amp rating for the switches... Failing that anyone know if theres a way using a multimeter to work out the amp rating of something..? Though I fear its probably a case of putting amps through it until it gets hot and thats your amp rating....! Ta for any thoughts/previous expereinces/guesses Ryan Discovery 1 (200 or 300) or Discovery II ??? Binnacle or Facia Switch ??? Do you have a Part No. for the switch you intend to use ??? . Quote Link to comment Share on other sites More sharing options...
pwam2006 Posted May 5, 2010 Author Share Posted May 5, 2010 Hi, sorry, yes a more useful amount information would've been good wouldn't it! Its the rear fog light switch on a Disco 1 that sits on the dash with the radio control, heated rear windscreen etc. Part No is AMR3751. Cheers Quote Link to comment Share on other sites More sharing options...
errol209 Posted May 5, 2010 Share Posted May 5, 2010 Am fitting a work light to the disco, 55 watt halogen. Wanting to use a spare standard discovery fog light switch to turn it on/off. Any thoughts as to whether I can run the power straight through the switch (55/12 =~ 5 amps) rather than have it switch a relay? I can't find the amp rating for the switches... Subject to confirmation, this type of switch is probably rated at most at 5A, and I'll bet the Disco has a relay in the circuit. (I haven't got the Disco wiring diagram to hand). Failing that anyone know if theres a way using a multimeter to work out the amp rating of something..? Though I fear its probably a case of putting amps through it until it gets hot and thats your amp rating....! Fridge Freezer's Theory of Land Rover Electricians strikes again. No. No. and NO. Without the manufacturer's data sheet (or a marking on the switch) there is no safe way of knowing. I appreciate you might have been joking, but let's not, please. The most risk-free route would be to splash out on the relay anyway, or re-think your choice of switch, unless someone can conjure up the rating for the switch. Quote Link to comment Share on other sites More sharing options...
pwam2006 Posted May 5, 2010 Author Share Posted May 5, 2010 I was joking about the 'test until fire' method. I did however hook up everything out of the car and it seems the switch is man enough to run the light (didn't get warm, no fire/explosions), so have installed it with no relay (I did have a relay at the ready, was trying to save on clutter!). I have a 5 amp fuse in line with the power feed, which hasn't blown yet, and I figure that this is a nice low ampidge such that if it was gonna melt/go bang, this would probably pop first. Had a look through the wiring diagram, wasn't immediately obvious that there was a relay anywhere, and I think...that the switch switches the multifucntion unit in someway (so as the foglights only work when the headlights are on..) so perhaps there is a ''relay'' in that? Makes for quite a smart installation, (it even lights up with the rest of the backlit switches ) Going to do the same with extra high beam spots (100W wipacs...think i might use a relay for them!! ) Thanks Quote Link to comment Share on other sites More sharing options...
PaulMc Posted May 5, 2010 Share Posted May 5, 2010 I've got one of the Discovery 1 front fog lamp switches (AMR4138), in pieces, in front of me. I would say that the contacts are OK for 5 amps, but I wouldn't be happy exceeding that. I would also say not to dismantle any of the Discovery 1 switches if you ever want to use them again Relays cost very little and enable you to keep the accessory supply wiring suitably heavy, to minimise voltage drop, without having a weak link. I'm using relays with all 3 of the Discovery 1 switches, that I'm using for additional lights, in my Discovery II - . Quote Link to comment Share on other sites More sharing options...
pwam2006 Posted May 5, 2010 Author Share Posted May 5, 2010 Cheers PaulMc, sorry you sacrificed a switch! the light running through it is 55W, so hopefully should'nt wander much above 5 amps, and if it does the inline fuse should pop anyway. The other lights will be relayed, and the switches for them placed in exactly the same place that you have them! (nice tidy job ) Quote Link to comment Share on other sites More sharing options...
PaulMc Posted May 5, 2010 Share Posted May 5, 2010 Cheers PaulMc, sorry you sacrificed a switch! the light running through it is 55W, so hopefully should'nt wander much above 5 amps, and if it does the inline fuse should pop anyway. The other lights will be relayed, and the switches for them placed in exactly the same place that you have them! (nice tidy job ) It's OK, I didn't sacrifice one of my new switches just to answer your question I had already taken apart an old one, that I picked up at an Autojumble, to see if I could replace the switch cap with a modifed blank cap (as I've done with Discovery II and post-2002 Defender switches). I've found out that doing this isn't really feasible with Discovery 1 Switches, as their construction, backlighting and tell-tale illumination are totally different to the later type of switches Also, the way they're constructed makes it very difficult to dismantle them without breaking them - . Small plastic clips and my ham-fists are not a good combination . Quote Link to comment Share on other sites More sharing options...
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