laurennn Posted October 7, 2018 Share Posted October 7, 2018 Hi all, I am a newbie here, just purchased my very own 1986 Mini Cruiser. I'm absolutely in love with it and most things seem to be in great working shape, but on my maiden voyage I had my first breakdown. There seems to be something going on between the battery and the alternator. Both seem to be in good working shape and are reading the way they should with a voltmeter indicating they are not the reason for the issue. The fuseable link for the alternator was pretty beat up, we replaced that and the issue persisted. The alternator just doesn't seem to be charging the truck battery (which is very new) enough to keep it running. After doing some probing we decided that it may be the voltage regulator...the one in there is definitely aftermarket and lookS like crap. Has anyone else had experience with these issues or replacing a voltage regulator? Is it possible that the 'house' battery is sucking all of the power from the alternator and thus not leaving enough for the truck battery? Should I try to remove the isolator so the alternator only charges the truck battery (and if so, could someone explain where I might find that)? Could it be something else? I'm planning on getting a couple new deep cycle batteries anyway, so not super concerned about not having the old one charged up. AND maybe I'm way off base! Any help or insight is greatly appreciated. Thank you! Quote Link to comment Share on other sites More sharing options...
WME Posted October 7, 2018 Share Posted October 7, 2018 Well the only "thing" between the alternator and the battery is the isolator. You should check the voltage at the alternator (14v+). Then check the voltage in for the isolator, should be alternator voltage. Then check the voltage at the truck battery, again same as alternator. The isolator looks like a little silver 35mm film can with large cables. OR a 3x3x6 box with fins on top. Usually on the driver side fender. If all else fails then follow the alternator wire. Which one do you have?? The film can isolator was common on older RVs. The truck battery voltage DOES NOT GO THROUGH this type of isolator. Quote Link to comment Share on other sites More sharing options...
Maineah Posted October 8, 2018 Share Posted October 8, 2018 I believe your regulator is internal to the alternator around 84 early 85 they switched. In a normal charging situation the coach battery would be the one to suffer before the truck. An open diode in a solid state isolator could cause you truck battery not to charge but the coach still would. You need a voltmeter. The solid state one is a small box with cooling fins on it. Quote Link to comment Share on other sites More sharing options...
laurennn Posted October 11, 2018 Author Share Posted October 11, 2018 Hi Mainah, turns out it was an external voltage regulator that fried the alternator after all. New alternator has an internal voltage regulator. Quick question for you about the overdrive: I’ve been told and read that you really shouldn’t use it as it can kill the transmission. I understand that it is a button with an on/off position. I currently have it in the off position, but driving to Rangeley I noticed a green light that says “overdrive” on the dash. If that light is on, does that mean the overdrive is engaged? And if so, even with the button in the off position, could something have happened internally to kick it into overdrive while driving on steep hills? i am new to this and just want to make sure I’m doing my best to maintain this puppy! Quote Link to comment Share on other sites More sharing options...
laurennn Posted October 16, 2018 Author Share Posted October 16, 2018 Seems it was the alternator and a fried connection to the coach battery that did it. She’s on the road again for now. Thank you! Quote Link to comment Share on other sites More sharing options...
Maineah Posted October 16, 2018 Share Posted October 16, 2018 On 10/11/2018 at 5:28 PM, laurennn said: Hi Mainah, turns out it was an external voltage regulator that fried the alternator after all. New alternator has an internal voltage regulator. Quick question for you about the overdrive: I’ve been told and read that you really shouldn’t use it as it can kill the transmission. I understand that it is a button with an on/off position. I currently have it in the off position, but driving to Rangeley I noticed a green light that says “overdrive” on the dash. If that light is on, does that mean the overdrive is engaged? And if so, even with the button in the off position, could something have happened internally to kick it into overdrive while driving on steep hills? i am new to this and just want to make sure I’m doing my best to maintain this puppy! I know it's nuts but when the light is on it's off. If it's off it's off it will not engage by itself. I have some insight to the OD from rebuilding transmissions I drove mine like I would a standard only used OD when it was not an issue to do so it was one of the few vehicles that I ever owned with an automatic but with most people it probably is a good ideal to leave it off unless you are on a long flat road. Here is what happens it's called converter slip in OD climbing hills or a long upgrade the converter slips far more so than in direct drive or even lower gears all this does is over heat the trans fluid not a good thing. I recommend trans flushes at 30 K as long as it has been done on a regular basis if it has a lots of miles leave it alone maybe just dump the fluid in the pan nothing more or you may be walking in a couple of weeks. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted January 29, 2019 Share Posted January 29, 2019 on my toy, the indash light, when illuminated, indicates the OD has been selected off. I have a 6 cylinder so my OD is effectively "different". I only turn the OD off when wanting the transmission to stay in 3rd gear for downhill compression braking. I have driven a 4 cyl toy & I expect your OD will be essentially useless except going down grade when you want to go fast. Quote Link to comment Share on other sites More sharing options...
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