Jack Posted April 20, 2008 Share Posted April 20, 2008 Folks as you know my rear bulbs have been blowing. Someone mentioned to me that it could be a voltage regulator problem as this would blow my bulbs and another sign of this would be the battery electrolyte level would also be reduced. Would this problem blow my main headlamps too? I have just checked the battery and it is nearly all gone :argh: So, how do I fix/replace the regulator?? Cheers Jack. Quote Link to comment Share on other sites More sharing options...
pop larkin Posted April 20, 2008 Share Posted April 20, 2008 The voltage regulator is the big black box fitted to the fire wall under the bonnet. Not sure how you go about testing it, but to replace it simply buy a new one. Or get a 12v conversion with an alternator, then you won't need to worry about the volatage regulator. Quote Link to comment Share on other sites More sharing options...
Jack Posted April 20, 2008 Author Share Posted April 20, 2008 Cheers Pop - just come in to check the thread - (24 hour interactive manual :shocked:) The problem is then that the GMC is 12 volt :argh: Any thoughts? Cheers Jack Quote Link to comment Share on other sites More sharing options...
pop larkin Posted April 20, 2008 Share Posted April 20, 2008 So your already on 12v then? Do the bulbs blow the moment you turn them on or after a while? is it all your rear bulbs, stop lights too? Are your headlamps blowing aswell? Do you still have the original harness in the GMC? I have made a new harness for the Chevy to include indicators, plus I added a fusebox into it as originally there were no fuses in the harness. If you are running the original harness without a fuseable link you could have a short to earth or voltage spike that would normay blow a fuse, but instead is blowing the bulbs :???. Quote Link to comment Share on other sites More sharing options...
Joris Posted April 20, 2008 Share Posted April 20, 2008 Did not this problem start to occur after you 6v to 12v (sex)change? Quote Link to comment Share on other sites More sharing options...
Jack Posted April 20, 2008 Author Share Posted April 20, 2008 Pop - no it is just the rear bulbs - the indicators, brake lights and headlamps are fine. They do not blow straight away..... The batterywas new last year but the level has dropped dramatically. Quote Link to comment Share on other sites More sharing options...
R Cubed Posted April 20, 2008 Share Posted April 20, 2008 Ok Jack, first things first.... 1... Is your truck 12volts now. ? 2... Does it have an alternator ? 3... Do you use the original regulator on the bulkhead ? 4... When the truck is running, ticking over and at medium revs, 1500rpm, do you know what the voltage is at the battery, get a voltmeter on it and check, should be no more than 14.4 volts. You say it is only the rear lights which blow ? if so are you fitting 6volt bulbs instead of 12volt !!!!!!!!! Quote Link to comment Share on other sites More sharing options...
Mark Posted April 20, 2008 Share Posted April 20, 2008 Earth problem Quote Link to comment Share on other sites More sharing options...
R Cubed Posted April 20, 2008 Share Posted April 20, 2008 Earth problem Earth problem, how does that cause the bulbs to blow !!! might cause them to stop working, but not to blow, it depends what the actual problem is with Jacks truck ............... Quote Link to comment Share on other sites More sharing options...
Jack Posted April 20, 2008 Author Share Posted April 20, 2008 Ok Jack, first things first.... 1... Is your truck 12volts now. ? 2... Does it have an alternator ? 3... Do you use the original regulator on the bulkhead ? 4... When the truck is running, ticking over and at medium revs, 1500rpm, do you know what the voltage is at the battery, get a voltmeter on it and check, should be no more than 14.4 volts. You say it is only the rear lights which blow ? if so are you fitting 6volt bulbs instead of 12volt !!!!!!!!! Hi Rich! Ok here are the answers: 1 - 12 volts and has been for nearly two years 2 - yes 3 - no 4 - will check this week.. It has been running perfectly for nearly 2 years :confused::confused: Quote Link to comment Share on other sites More sharing options...
R Cubed Posted April 20, 2008 Share Posted April 20, 2008 As a quick suggestion I would say the regulator for the alternator is duff, but without knowing the volts as in my previous post cant say for sure. Quote Link to comment Share on other sites More sharing options...
Tony B Posted April 20, 2008 Share Posted April 20, 2008 If it is on an alternator, and the connections are clean, then can't be anything but internal. some alternators have an added gizmo for modern cars. If not connected it can cuase overcharging, but you can't connect on an old vehicle, it's to do with tach drive. What voltage are you getting at the battery wihen idiling and when reved? If its over 13.8 volts the problem is the alternator. Quote Link to comment Share on other sites More sharing options...
Jack Posted April 20, 2008 Author Share Posted April 20, 2008 Great stuff will check it this week! The alternator was brand and came with the 12 volt kit. Rich - you should move to Dorset :whistle: Quote Link to comment Share on other sites More sharing options...
R Cubed Posted April 20, 2008 Share Posted April 20, 2008 Great stuff will check it this week! Rich - you should move to Dorset :whistle: Is that an offer :wow: Do you have big sheds in Dorset.........:idea: :idea: Quote Link to comment Share on other sites More sharing options...
abn deuce Posted April 20, 2008 Share Posted April 20, 2008 wasnt there a fellow from Dorset or some such place that had two sheds ? name was Jackson I think , recall him from Monty Python ??? Quote Link to comment Share on other sites More sharing options...
Chrisg Posted April 20, 2008 Share Posted April 20, 2008 yep two sheds jackson Quote Link to comment Share on other sites More sharing options...
Jack Posted April 23, 2008 Author Share Posted April 23, 2008 4... When the truck is running, ticking over and at medium revs, 1500rpm, do you know what the voltage is at the battery, get a voltmeter on it and check, should be no more than 14.4 volts. Ok - during the brief moment the GMC was running :argh: it reached no more that 14 volts right through the rev range........ Any thoughts :sweat: Cheers Jack. Quote Link to comment Share on other sites More sharing options...
R Cubed Posted April 23, 2008 Share Posted April 23, 2008 Well that sounds ok as long as it stays at no more than 14volts. The alternator should be good for many years so would not think it is that, the bulbs you are replacing, are you sure they are 12volt ? if you are fitting 6v ones then after a short period they will blow, are you sure they are blowing and its not just a dodgy connection somewhere, after you have taken them out have you tried them on a battery !!!!!!!!!! As you say the other bulbs are ok leads me to think that the ones you are putting in are 6volt, but then I am not there to see :??? Quote Link to comment Share on other sites More sharing options...
Tony B Posted April 23, 2008 Share Posted April 23, 2008 Yeah, the alternator sounds right, bad connection or dodgy wire. Quote Link to comment Share on other sites More sharing options...
Jack Posted April 29, 2008 Author Share Posted April 29, 2008 Ok chaps - stuck the volt meter on them tonight and one side is ready 12v and the other 11.9v so can't see a problem there. Perhaps it may be the bulbs I get from Halfords..........! Quote Link to comment Share on other sites More sharing options...
Guest catweazle (Banned Member) Posted April 29, 2008 Share Posted April 29, 2008 HALFORDS.Jack stop wasting everyones time.:-D:-D:-D Quote Link to comment Share on other sites More sharing options...
Degsy Posted April 29, 2008 Share Posted April 29, 2008 HALFORDS.Jack stop wasting everyones time.:-D:-D:-D OHHH Gawd Jack, how many times, local auto elec factor:banghead: Quote Link to comment Share on other sites More sharing options...
Chrisg Posted April 29, 2008 Share Posted April 29, 2008 OHHH Gawd Jack, how many times, local auto elec factor:banghead: And cheaper Quote Link to comment Share on other sites More sharing options...
Jack Posted April 30, 2008 Author Share Posted April 30, 2008 And great - now you tell me. What sort of site is this - we are supposed to help each other :argh::argh::argh: - might crash the site again out of temper. :coffee: Quote Link to comment Share on other sites More sharing options...
Degsy Posted April 30, 2008 Share Posted April 30, 2008 This was a common problem on the tippers we used to operate, they were of course 24 volt but fitting heavy duty 28 volt always cured the problem. Unfortunately I don't know of any heavy duty 12/14 volt bulbs but try 2 GOOD quality bulbs, if they fail then I think that the wiring is the likeliest culprit. Quote Link to comment Share on other sites More sharing options...
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