darthdicky Posted August 26, 2009 Share Posted August 26, 2009 I've got one of those red FIA type cut off switches which also has the alternator protection bit I think (there's about 5 wires on it). It's mainly there as an extra bit of theft-proof-ness, though if something does go wrong then it's useful to have there. Problem is, when I take it out my radio looses its memory and all the default settings, so when I turn it on I just get white noise, loudly. Question is, can I put an inline fuse holder across the two terminals with maybe a 2 or 5 amp fuse in there, so that the radio memory stays, and maybe the interior light, but trying to start the engine without the red key in there blows the fuse immediately. Would this then mess up it's function as an emergency cut off too? Would prefer not to have to run more wires directly from the battery to behind the dash if possible. Anyone else done this? Richard Quote Link to comment Share on other sites More sharing options...
pinny Posted August 26, 2009 Share Posted August 26, 2009 no problem thats what ive got a 5amp fuse to keep the radios memory so no probs if you turn the ignition on while the isolator is off the glow plugs will blow it straight away Quote Link to comment Share on other sites More sharing options...
garymorris Posted August 26, 2009 Share Posted August 26, 2009 Hello , I use the same thing on my 110 cut off switch with a 5amp resettable fuse and it works well Cheers Gary Quote Link to comment Share on other sites More sharing options...
Aragorn Posted August 26, 2009 Share Posted August 26, 2009 Surely that means it wont acutally cut the engine though? With the engine running, the amount of current required to keep the stop solenoid open is much less than 5A? I would simply run a direct feed from the battery to the stereo's memory pin. Quote Link to comment Share on other sites More sharing options...
sgnas Posted August 26, 2009 Share Posted August 26, 2009 Hmmm. I think a 5amp fuse will keep the stop solenoid open too. So no use as an emergency cut out. Memory wire on a radio is usually fused at 0.5amp. Could try that, I don't know what the stop solenoid pulls! I know it stays open at low (<8v)voltages so I suspect it is very little. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted August 26, 2009 Share Posted August 26, 2009 Replace fuse with a ~1-10 ohm resistor and that should have a similar effect, you may want a beefy one (1W ish) to prevent it burning out if you forget to flick the isolator on before trying to start the car, or you could add a diode and a dedicated feed wire direct to the stereo, that way nothing other than the stereo is getting power & nothing can back-feed or draw too much current. Knowing how much current your stereo draws would be a good start, the higher value resistor you can get away with the better. Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 27, 2009 Share Posted August 27, 2009 No the fuse keeps the circuit open. Just take the simple way out. Take a live from the live side of the switch. i.e. the battery terminal of the switch. I have mine wired this way, not only for the radio memory but the alarm and the interior lights. There must be at least three posts of mine on this subject. mike Quote Link to comment Share on other sites More sharing options...
SteveG Posted August 27, 2009 Share Posted August 27, 2009 Sorry for being a smart ass, but just turn your stereo down before you get out, and hit the tuning button and volume when you get in. It's dumb ass Quote Link to comment Share on other sites More sharing options...
darthdicky Posted August 27, 2009 Author Share Posted August 27, 2009 Hmmmm... well a variety of options there (retuning and turning it down is not an option as it also has a load of equaliser settings I want stored and all the silly flashing lights need to be turned off). I'm not sure my Sony stereo has a seperate pin for the memory, it just needs a permanent 12v supply to it which is on a fairly hefty wire at the moment. My next thought is to put another switch down on the seatbox, so when the switch is on and the key is off it runs through a fuse, but turning the switch off cuts this link and the engine. Would this work? Can the Carling switches be used like this, I seem to remember they have a 20amp limit which is more than enough with a 5amp fuse. Rich Quote Link to comment Share on other sites More sharing options...
ChrisM_110 Posted August 27, 2009 Share Posted August 27, 2009 I use an isolator for security, but have run a seperate feed for cigar lighter, stereo memory, alarm and interior lights. It runs via a second fusebox (but you could just use an inline fuse) fed straight off the battery positive before the isolator, natch. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted August 27, 2009 Share Posted August 27, 2009 What about getting a simpler stereo? I'm thinking analogue tuning and a simple volume knob... Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 27, 2009 Share Posted August 27, 2009 I use an isolator for security, but have run a seperate feed for cigar lighter, stereo memory, alarm and interior lights. It runs via a second fusebox (but you could just use an inline fuse) fed straight off the battery positive before the isolator, natch. Exactly Chris. Just like I have mune set-up. Too simple that way though mike Quote Link to comment Share on other sites More sharing options...
darthdicky Posted August 27, 2009 Author Share Posted August 27, 2009 Not really Mike, I don't currently have any wire to go from the battery to the radio and don't really want more connections on the battery, but I do have a fuse holder and a switch - if I can make it work properly with what I've got it's a better solution for me. John, don't think a simple stereo would run the daft sub in the back and that's not going anywhere - can just about hear the radio over the TDi at motorway speeds now! Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 28, 2009 Share Posted August 28, 2009 You have plenty room to add wires to the FIA switch. Well I had anyway. mike Quote Link to comment Share on other sites More sharing options...
Eightpot Posted August 28, 2009 Share Posted August 28, 2009 What about a little battery pack from maplins and a few AA batterys/2 x 6v tongue ticklers to give a 12v supply, enough to keep the memory alive and tucking it down the back of the dash - can't imagine the memory on a stereo will draw very much? Quote Link to comment Share on other sites More sharing options...
Roverdrive Posted August 29, 2009 Share Posted August 29, 2009 If you have the FIA switch wired correctly, the fuse would not keep the engine running. I am assuming it is a diseasel, and if so, the stop solenoid should be wired through the auxiliary contacts on the back of the switch that are closed with the switch in the on position, and open with it in the off position. This is what stops the engine. The other pair of contacts are open with the main switch in the on position. These are used to connect a ceramic type resistor between the alternator side of the switch and earth. As soon as the main switch is turned off, the alternator is grounded out to earth via the resistor. You can see the problem here can't you? With a fuse across the main contacts, and the resistor to earth you will blow the fuse anyway. If you have not fitted the ceramic resistor, it will work if you use the switch purely as an isolator, but if you use it to kill the engine, I believe you can damage the alternator which is why it is there in the first place, unless it is purely to drop the voltage. To be honest I am not 100% sure on that score. Hope this is of some assistance Quote Link to comment Share on other sites More sharing options...
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