18+ Volts on Idle Alternator Issues

[PebbleCruiser]

(2003 2UZ-FE ROW LC100) Day 9 of a long road trip, this morning from a cold start the battery voltage around 13V and after ignition the voltmeter on the dash immideatly jumped to 16V then started increasing to 19V and can hear the fan blower motor begging for its life as well as the stereo system. So quite sure the cluster display voltmeter is working correctly and alternator is over feeding.

Checked the alternator sense fuse under the hood and its good, disconnected a bunch of other fuses but to no avail. I suspect the Voltage Regulator or the Alternator diodes are shorted but past 5k km everything was perfectly ok with no signs of bad alternator/battery.

Has anyone had similar issues? What should I check? Completely stuck at the hotel parking lot as I'm scared if I increase rpms driving I will fry all electrical systems

 

[PebbleCruiser]

Clicky on the video you can see the voltage jumps to 16V+

 

[badlander]

I think the sense fuse is very sensitive to contact condition. I had high voltage one time and pulled the fuse and reinserted it and all has been fine ever since. Did you actually pull it or just check visually?

 

[PebbleCruiser]

I think the sense fuse is very sensitive to contact condition. I had high voltage one time and pulled the fuse and reinserted it and all has been fine ever since. Did you actually pull it or just check visually?

The 7.5 amp Sense fuse I tried with it removed and re inserted and same results. Perhaps this points to a fried Voltage Regulator or Alternator?

 

[PebbleCruiser]

Update: New battery and upgraded to a 100amp alternator with a slightly bigger casing that needed some shaving and all working again, back on the road! Everything is working but the stereo, probably fried the amp.

After the road trip I will surely upgrade alt wirings and rebuild the old 80amp alternator as a spare.

 

[Seanshine]

Wish I had seen this sooner, I had the same thing happen. I had a lot of weird things happen. Bulbs burned out, radio stopped working, antaenna wouldn't raise or lower. Found the charge voltage was 18+. I replaced the alternator and when I did I believe it was the power steering pump hoses leaking onto the alternator which caused it. I'm not sure though, but I replaced and fixed the leak with zero problems so far.

 

[jaewastooshort]

Posted about this somewhere else, but had a high voltage warning pop up the other night along with my stereo going out entirely. Thanks to @NoVaGator I "inspected" the fusible link setup and (after breaking a couple of brittle plastic pieces) bought a replacement from Cruiser Patch. Got it in and it fixed my issue. Now to figure out what (apparent) fuse blew that's keeping my primary amp from working.

I had this issue rather suddenly and after posting someone suggested the fusible link block being a possible problem. My plastic was so brittle I broke a couple of pieces while trying to get everything disassembled to inspect, but there was some corrosion around all the connections. With the new plastic block in-hand and wire terminals cleaned up, I reassembled and the over-charge issue was gone.

I would still suggest disassembling and cleaning all those contacts even if your alternator replacement corrected the issue...
- disconnect fuse block from terminal
- carefully remove lid
- remove 7.5A fuse
- carefully pry on tabs holding lower cover to remove it and access screws/small bolts (paint/mark or use tape on wires to note correct locations)
- NOTE: bolts must be removed before 100A and 140A fuses can be removed from block
- use a very thin awl or similar to carefully remove the small terminals that connect with the 7.5A fuse
- clean all the wire terminals and reassemble

If you don't feel comfortable dis-assembling, you might use a contact cleaner spray like "CorrosionX" in the contacts for the 7.5A fuse.

I bought a reman alternator from Toyota but have not installed it as the issue has not occurred again.

 

[PebbleCruiser]

I had this issue rather suddenly and after posting someone suggested the fusible link block being a possible problem. My plastic was so brittle I broke a couple of pieces while trying to get everything disassembled to inspect, but there was some corrosion around all the connections. With the new plastic block in-hand and wire terminals cleaned up, I reassembled and the over-charge issue was gone.

I would still suggest disassembling and cleaning all those contacts even if your alternator replacement corrected the issue...
- disconnect fuse block from terminal
- carefully remove lid
- remove 7.5A fuse
- carefully pry on tabs holding lower cover to remove it and access screws/small bolts (paint/mark or use tape on wires to note correct locations)
- NOTE: bolts must be removed before 100A and 140A fuses can be removed from block
- use a very thin awl or similar to carefully remove the small terminals that connect with the 7.5A fuse
- clean all the wire terminals and reassemble

If you don't feel comfortable dis-assembling, you might use a contact cleaner spray like "CorrosionX" in the contacts for the 7.5A fuse.

I bought a reman alternator from Toyota but have not installed it as the issue has not occurred again.

Thanks for the detailed explanation and I did read about the 98-02 fuses at the + battery post being a failure point but on my 03 I have fusible link with no detachable fuses and a little different wiring I believe and I did clean all fuses but simply my 5 year old alternator was shot.

And @Seanshine brought a good point about leaky P.S. fluid dripping and shorting the alternator. But still not what happened to me and all my PS hoses were replaced 5 years ago when I rebuilt the engine and most of the wear-n-tear components (not wiring unfortunately)

On another subject: I did overload the AHC system with the trunk filled to the brim and the rear is in low position and the dash light on low but the front is in normal height and I’m blinding everyone in front. Wondering IF unloading everything, putting the front and rear on Low and then pulling the AHC fuse/relay/pump (so many options) would force the front to be on low and match the overloaded rear height cause any issues going highway speeds (no more than 120kmh (75mph))

I’m wondering if that would be better than it is now with front in neutral and rear in low height.