7tonemonte Posted June 23, 2013 Share Posted June 23, 2013 I think I want to do an upgrade to the 12SI altenator for my Monte, as on the way home from Carlisle either my altenator or voltage regulator seems to be acting up, car died at the toll booth I did see this post with the plug and play harness for the altenator. Link to wiring plug Question here will be, what altenator part number would I be looking for, #of amps...etc... Im not running any crazy amps,fuel pumps, running lights,anything like that, so I dont think I need all the way up to 100 amp, do I? Give me some realistic suggestions here, I am a painter remember, not a mechanic, I want simplicity Also, am I taking a chance upgrading that with my 40 year old wiring harness? Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted June 23, 2013 Author Share Posted June 23, 2013 Im not sure if this is the route Ill go, but heres another question, why didnt my generator light come on? I just turned the key to the on position and it lights up fine. Basically the car is charging over 14volts while running, as soon as you turn on the headlights it starts dropping, it went down under 13 before I turned them off and went right back up to 14+ again. When it was hot from the ride home it was reading just under 14 while running. And oh yea, thanks to the 1 person that actually got out of thier car and helped push, the others just sat and complained waving thier arms and yelling. People really suck! Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted June 23, 2013 Share Posted June 23, 2013 it may be as simple as a ground problem Tony, check the alt to block, the alt needs to ground to the block, check the battery to fender ground, there is also a ground from the regulator to core support, and if the battery ground is to the alt upper bracket, it has to have a good ground to the alt and intake manifold, try cleaning these grounds and see if it helps Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted June 23, 2013 Author Share Posted June 23, 2013 Checked all them again this am Sam, all is good. My regulator is looking pretty corroded, and both items are original to the car, it's believeable that either one could have kicked it! Of course it happens when I actually NEED the car due to the Denali going in for a front axle rebuild. Always the way hopefully someone has parts in stock today I may have to look into the upgrade for later and just get it back on the road Quote Link to comment Share on other sites More sharing options...
wallaby Posted June 23, 2013 Share Posted June 23, 2013 You probably had a diode fail in the alternator. Depending on which one fails, it may/may not trigger the gen light to come on. Even if we knew this to be true, I'd still replace both the alternator and regulator as a pair. Most replacement regulators are an electronic type, and work fine but may look different than the large original mechanical type.. I mounted my old cover onto the new regulator and it looks right. As far as the alternator "upgrade" goes, read through this page and get an idea of what's happening: LINKY I did some of their suggested mods (basic larger gauge wire between the alt and regulator buss) and retained the original type external regulated system. I have electric fans, AC, a remote amp for my stereo, halogen headlamps, and the original system works great and has for years. There are several options with "upgrades", and some of them work more poorly than the original setup. Again; read through the link above and make sure that the changes you make are going to improve things. Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted June 23, 2013 Author Share Posted June 23, 2013 Thanks for that info Mark, just got back from parts store, my alt tested fine, still got both parts to put in anyway. I may bolt the old alt in just to see what's happening. Quote Link to comment Share on other sites More sharing options...
7tonemonte Posted June 24, 2013 Author Share Posted June 24, 2013 Just went with a stock replacement alternator and regulator today because I need the car this week. The alt tested fine at the store but I replaced it anyway. Maybe it was acting up when it got hot? How would I test to see if the generator light is working correctly? It comes on if I turn the key on but what would I do to test to see if works while car isn't charging? Quote Link to comment Share on other sites More sharing options...
Toppless72 Posted June 24, 2013 Share Posted June 24, 2013 Dis-connect the wire going to it or remove the belt. If the motor is running and it's not charging the light should come on. Quote Link to comment Share on other sites More sharing options...
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