msavides Posted November 6, 2007 Share Posted November 6, 2007 Well I was wondering if any of you have had this problem and if you know the solution. I checked my voltage at the battery and it shows 14.2 volts but the stupid voltage gauge is pointing right between 16-18. What is the deal. It freaked me out I thought it was overcharging until I grabbed my meter and checked it. Mark Link to comment Share on other sites More sharing options...
91path Posted November 7, 2007 Share Posted November 7, 2007 mine shows close to 18v too. now im not as worried about it. good deal!!! :tonguefinger: Link to comment Share on other sites More sharing options...
88pathoffroad Posted November 7, 2007 Share Posted November 7, 2007 Do you have 14 volts with it running or off? If you have 14V with the engine off, it could very well be overcharging. Link to comment Share on other sites More sharing options...
msavides Posted November 7, 2007 Author Share Posted November 7, 2007 Do you have 14 volts with it running or off? If you have 14V with the engine off, it could very well be overcharging. 14 volts while running only. drops down to 12.4- 12.8 when shut off. Mark Link to comment Share on other sites More sharing options...
Roost Posted November 8, 2007 Share Posted November 8, 2007 (edited) 14 volts while running only. drops down to 12.4- 12.8 when shut off. Mark Are you testing voltage at the battery or the alternator? There can sometimes be a dramatic difference in the two, depending on what accessories you are running at the time. Just a thought. Edited November 8, 2007 by Roost Link to comment Share on other sites More sharing options...
94extreme Posted November 8, 2007 Share Posted November 8, 2007 alt charges at ~17V Link to comment Share on other sites More sharing options...
88pathoffroad Posted November 9, 2007 Share Posted November 9, 2007 Alternators should stop at or near 15V, not 17. I've had an old Ford bucket truck pop it's voltage regulator and burn out every light bulb on the truck before. What a PITA! Link to comment Share on other sites More sharing options...
msavides Posted November 9, 2007 Author Share Posted November 9, 2007 Alternators should stop at or near 15V, not 17. I've had an old Ford bucket truck pop it's voltage regulator and burn out every light bulb on the truck before. What a PITA! tested at battery only. mark Link to comment Share on other sites More sharing options...
Roost Posted November 9, 2007 Share Posted November 9, 2007 (edited) tested at battery only. mark Find out where you voltage indicator is hooked up and that will start you on you path of TS this phenom. If it located near the alternator, then the indication is proper. If it more "down stream", you would seem to have another problem to find. I hope this helps. Semper Fi Edited November 9, 2007 by Roost Link to comment Share on other sites More sharing options...
ANDY Posted August 5, 2011 Share Posted August 5, 2011 hey sorry to bring up a really old thread but my gauge is acting up, anyways i just replaced my alternator yesterday because my old one was making a crazy squeal and was reading 16-17 volts so i was like okay ill replace it so i did and its still reading 16-17 volts but i hooked it up to the midtronic battery tester and it was reading 13.9-14.1 volts runnung and we hooked it up to the VAT? load tester machine and reading 14v so im kinda losted and kinda wanna figure this out. can it be a bad ground or a fuse ? any new help would be appreciated andy Link to comment Share on other sites More sharing options...
MY1PATH Posted August 5, 2011 Share Posted August 5, 2011 inside your cluster, you should find an analog voltage regulator (I think its all pre 89's) it will look like to flat blades with a coil of wire arround one and a tiny screw that appears to push them apart. you will have to be careful when you open the cluster as 20 year plastic is brittle (esp the clear plastic) once you get to the regulator plug the unit back in and turn the screw untill the guage is more accurate. your othe guages (water, oil and fuel) will likely move as well. Tach and spedo are un-effected by this. Link to comment Share on other sites More sharing options...
Tungsten Posted August 5, 2011 Share Posted August 5, 2011 Is this the same for 90+ models? My voltage gauge would sometimes just read the max 18v for no apparent reason what so ever. Link to comment Share on other sites More sharing options...
MY1PATH Posted August 5, 2011 Share Posted August 5, 2011 I think 90+ clusers got electronic regulators, and I do belive there is a thread on here somewhere that covers the replacement of said units. INCL. a radio shack part number if I'm not mistaken. Link to comment Share on other sites More sharing options...
sewebster Posted August 5, 2011 Share Posted August 5, 2011 I believe there are at least two voltage regulators on the truck. The one in the cluster which is specifically to drop the voltage for the gauges, and the main one to regulate the output of the alternator? The output of the one in the cluster is NOT what the voltage gauge reads, or else it would always read the same thing... 8V or whatever it is supposed to be. The cluster one is the one that usually dies though... Link to comment Share on other sites More sharing options...
MY1PATH Posted August 5, 2011 Share Posted August 5, 2011 I thought the cluster regulator steps down the existing voltage and the gauge is scaled to that. example; 14.4v would be 8v ,13.5 would be 7.5 etc... Or maybe it needs regulated power to display the current voltage. example; a Multi-meter may run off of 4 LR44 batteries(4.8v total) but it does not show 4.8v all the time, it shows whatever you attach the leads to. Regardless, we are talking about a problem the cluster, the regulator on the alty is fine or else his multi-meter would read wrong. I have not played with an 87 volt meter cluster, there may be a calibrator directly on it. once you carefully pop it open take some detailed pictures so we can shed some light on this. Link to comment Share on other sites More sharing options...
sewebster Posted August 5, 2011 Share Posted August 5, 2011 I thought the cluster regulator steps down the existing voltage and the gauge is scaled to that. example; 14.4v would be 8v ,13.5 would be 7.5 etc... Or maybe it needs regulated power to display the current voltage. example; a Multi-meter may run off of 4 LR44 batteries(4.8v total) but it does not show 4.8v all the time, it shows whatever you attach the leads to. Regardless, we are talking about a problem the cluster, the regulator on the alty is fine or else his multi-meter would read wrong. I have not played with an 87 volt meter cluster, there may be a calibrator directly on it. once you carefully pop it open take some detailed pictures so we can shed some light on this. Ah, yeah, that could be a good point. I think the regulator always steps to 8, regardless of the input voltage (not entirely sure) but maybe the voltage gauge can get screwed up by getting the wrong voltage from the cluster reg (used as power) even when it's reading somewhere else. Link to comment Share on other sites More sharing options...
Tungsten Posted August 5, 2011 Share Posted August 5, 2011 I think the best spot to probe for voltage would be through the cig lighter socket. Link to comment Share on other sites More sharing options...
Slartibartfast Posted August 7, 2011 Share Posted August 7, 2011 Confirm the lighter socket against the battery first, there's a bit of wiring, a fuse, and the ignition column between them. Shouldn't make a difference, but might. Link to comment Share on other sites More sharing options...
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