AWP Posted July 15, 2015 Share Posted July 15, 2015 I fitted a red key Battery Isolator Switch (Halfords) using 27 inch extra leads on the positive terminal side of my 2010 Swift Escape 624. Now getting the yellow engine management warning light up on the dash display? I removed the switch, started the Fiat Ducato engine 6 times and then this yellow warning light disappeared. Can anyone explain why putting in this simple in line switch is causing this problem? Cheers. Link to comment Share on other sites More sharing options...
AWP Posted July 21, 2015 Author Share Posted July 21, 2015 Anyone out there, ET call home :-) Link to comment Share on other sites More sharing options...
markh1 Posted July 22, 2015 Share Posted July 22, 2015 Since you've put an isolator switch between the battery and the vehicle, you are stopping any power getting to items that need it, even when the ignition is off, your ECU for example, hence the warning light, not sure why you want to isolate your battery? If it's for security they are child's play to bypass Link to comment Share on other sites More sharing options...
sshortcircuit Posted July 22, 2015 Share Posted July 22, 2015 Which battery are you attempting to isolate, starter or leisure? If you have fitted to starter battery I would not think you will get any warning lights until you switch it back on and then do they clear when you attempt to start? Link to comment Share on other sites More sharing options...
AWP Posted July 22, 2015 Author Share Posted July 22, 2015 Connected to positive side of Vehicle Starter Battery. When l switch back on and start engine the management warning light on even after starting / turning off engine 6 or 7 times. Link to comment Share on other sites More sharing options...
sshortcircuit Posted July 22, 2015 Share Posted July 22, 2015 Why are you isolating the starter battery? Link to comment Share on other sites More sharing options...
AWP Posted July 22, 2015 Author Share Posted July 22, 2015 Obvious, to avoid battery drain if in storage for several weeks. Quicker than lifting floor to undo battery terminal. Link to comment Share on other sites More sharing options...
sshortcircuit Posted July 22, 2015 Share Posted July 22, 2015 Obvious???? Pretty obvious that the ECU sees a fault when you isolate and switch back on. Fit a solar panel and then forget. Link to comment Share on other sites More sharing options...
Keithl Posted July 22, 2015 Share Posted July 22, 2015 sshortcircuit - 2015-07-22 6:58 PM Obvious???? Pretty obvious that the ECU sees a fault when you isolate and switch back on. So why doesn't it throw a fault when reconnecting without the isolator switch? My thoughts would be that you have introduced an excessive resistance and hence increased voltage drop across the positive lead and the Battery Monitoring System (BMS) is seeing this as a fault. Two suggestions, first refit and then get the error codes read to find out why, or second, shorten the additional leads as much as possible and try again (although I doubt this will work as these switches do tend to have an inherently high resistance). Keith. Link to comment Share on other sites More sharing options...
Tracker Posted July 22, 2015 Share Posted July 22, 2015 I don't know if or why it would make a difference but you could try isolating the negative instead of the positive? Ignore the critics, it makes perfect sense to me to isolate the battery to preserve it's charge and longevity when not in use for a while - and it's certainly cheaper, simpler and more reliable than a solar panel, regualator and split charging relay set up - although a decent solar panel set up would keep all the batteries charged. When vehicles are in for extended repairs the batteries are generally disconnected and maybe there is a certain procedure to be followed when reconnecting? You could try a cheap error fault code reader to try and establish just what it is the ecu does not like? Something like this works for me - http://www.amazon.co.uk/dp/B00JA0LNQQ/ref=pd_lpo_sbs_dp_ss_1/277-3717868-4156444?&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=lpo-top-stripe&pf_rd_r=0EKJXJ06HPR539462R3J&pf_rd_t=201&pf_rd_p=569136327&pf_rd_i=B006JXYH0G Link to comment Share on other sites More sharing options...
StuartO Posted July 23, 2015 Share Posted July 23, 2015 Keithl - 2015-07-22 7:48 PM .......these switches do tend to have an inherently high resistance). A battery isolator switch is designed to have very low resistance when closed. I'm afraid Keith's statement is nonsense. Link to comment Share on other sites More sharing options...
sshortcircuit Posted July 23, 2015 Share Posted July 23, 2015 StuartO - 2015-07-23 8:01 AM Keithl - 2015-07-22 7:48 PM .......these switches do tend to have an inherently high resistance). A battery isolator switch is designed to have very low resistance when closed. I'm afraid Keith's statement is nonsense. Thanks, saved me posting. Possibly a totally different fault and worth getting fault codes read for a correct diagnosis. Link to comment Share on other sites More sharing options...
Tracker Posted July 23, 2015 Share Posted July 23, 2015 If the isolator switch is faulty and does have high resistence it will get very warm when high curent flows like when starting the van. If it stays cold to the touch it is probably not high resistence. Link to comment Share on other sites More sharing options...
AWP Posted July 23, 2015 Author Share Posted July 23, 2015 Thanks guys, I plan to try a d get Fiat to code test for me at some point. Strange such a simp!e mech add causes an elect glitch. I must admit I thought a resistance / voltage drop may have caused the problem. Time will tell I guess. Solar panel next year maybe. Link to comment Share on other sites More sharing options...
lennyhb Posted July 25, 2015 Share Posted July 25, 2015 AWP - 2015-07-22 6:38 PM Obvious, to avoid battery drain if in storage for several weeks. Quicker than lifting floor to undo battery terminal. You really can't do that unless you want to take the van to a dealer to get the electrics reset every time you turn the switch off. The Fiat handbook states when changing a battery you should connect another battery to the jump terminals to keep the electronics powered. That should have given you a clue to the fact you can't fit an isolator switch. Link to comment Share on other sites More sharing options...
AWP Posted July 26, 2015 Author Share Posted July 26, 2015 lennyhb - 2015-07-25 4:31 PM AWP - 2015-07-22 6:38 PM Obvious, to avoid battery drain if in storage for several weeks. Quicker than lifting floor to undo battery terminal. You really can't do that unless you want to take the van to a dealer to get the electrics reset every time you turn the switch off. The Fiat handbook states when changing a battery you should connect another battery to the jump terminals to keep the electronics powered. That should have given you a clue to the fact you can't fit an isolator switch. I have not read / heard of this 2nd battery need, what do you do when you already have a flat battery then drag it to a Fiat Dealer -- No way! As I have already said above re-connect earth start up & turn off 6 times to reset and eng man light goes out. Would it be possible to use thin wire & fuse across Isolator Switch terminals to keep some feed for say clock and ECU to get round the problem? Link to comment Share on other sites More sharing options...
Keithl Posted July 27, 2015 Share Posted July 27, 2015 AWP - 2015-07-26 10:48 PM Would it be possible to use thin wire & fuse across Isolator Switch terminals to keep some feed for say clock and ECU to get round the problem? But surely that would defeat the whole object of fitting an isolator, namely to prevent drain on the battery? You cannot restrict what is drawing power or even limit power drawn by adding a fuse across the isolator, you would have to 'switch off' individual components which would be very, very difficult without drastic wiring mods. You have already proved you can reconnect the battery (albeit without the isolator) and successfully restart the engine so in the short term why not just remove the negative terminal when leaving the MH for any length of time? Unless you have an alarm (or tracker) fitted in which you must keep this powered to remain operational. Just my thoughts. Keith. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 27, 2015 Share Posted July 27, 2015 Using a supplementary battery to maintain vehicle electronics (in particular a radio’s security code) is a commonly used ploy when replacing a vehicle’s starter-battery. https://www.google.co.uk/?gws_rd=ssl#q=changing+vehicle+battery+radio I can’t find any reference to it in the Fiat handbook though. AWP’s primary reason for fitting a remote isolator switch was to avoid having to remove the cab-floor ‘lid’ that cover’s the battery compartment. Disconnecting the battery’s negative terminal would perform the same task as the switch, but the lid would need to be lifted to access the negative terminal. Link to comment Share on other sites More sharing options...
tonyishuk Posted July 27, 2015 Share Posted July 27, 2015 I had a Caterham which had an isolator switch for the starter battery. Probably not quite the same loading as a Fiat Diesel engine to start, but need more than a few amps to start a high compression engine from a small battery. However I found that some isolator switches have a much higher reistance to others and binned several purchased over the internet and Halfords. They over heated with the current flow. I ended up with one from Demon Tweeks. Rgds Link to comment Share on other sites More sharing options...
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