HOTRNHELL

While on the way home now the check gauges light came on and there was very low voltage on the gauge. Stopped at autozone and they said alternator was shot. Ok so I went across the street for 2nd opinion at checker and yup again alternator bad. Bought one and replaced it soon as I got home. Problem is this when I got home to replace ALT the passenger battery had blown the fill cap off and was boiling hot. After replacing ALT the batt voltage on passenger batt is reading at 18+ volts and starting to boil again. I took off all the batt cables and cleaned and replaced them. Still boiling passenger side. Took batt down to checker and they say all good. Is it ok to run the truck with just driver side batt connected and leave negative cable off passenger batt?? What gives is there a volt regulator that can be checked and or replaced? where is it located and how to test??


Please help going on trip tomorrow for work and need to fix asap.

pind

your battery temp sensor underneath the driver's side battery, is not reading correctly.

The ecm determines the rate of charge by the battery temp. when the sensor malfunctions, it tends to make the alternator charge like mad, to try and charge the drivers side battery.

being that the charge line from the alternator, goes directly to the passenger battery first, it takes the hit.

Make sure that sensor is making contact with the bottom of the battery at all times. Test it to be sure it is working as well.

justme-

Make sure you don't make the same mistake I did wit that- I used on of those anti acid mats under the batteries which keep s the sensor from ever reading the battery accurately.

Bearing in mind the nature of the wiring on the batteries- if the passenger battery is disconnected the drivers side will simply take the hit instead.. same problem.

bent valves

If the battery temp sensor was bad, both batteries would be boiling. The reason the passenger side is boiling and not the driver's side is caused by a poor battery connection on the driver's side.

The alternator is connected to the passenger side battery and the PCM, which tells the alternator how much voltage is needed, is connected to the driver's side. A poor connection will make the PCM think voltage is low and crank it up. One easy test is to run the engine and use a DVM to measure each battery. Be sure to connect the DVM leads to the center of the battery posts not the clamps. You will see a high voltage on the passenger side.

Easy fix - clean the terminals.

HOTRNHELL

Thanks for the suggestions all. Well I was up all night trying to figure this out. ended up short on time as had a trip out of town to work starting today had drop truck at *********** to let them handle it as I was worried the computer controler was bad. Ended up being the **** cables as you all said but i got the info too late. Oh well $400 later they diagnosed it and got her runnin again. It would not hurt quite as bad if they had done a good job but now I'm really ****** because they neglected to hookup my fuelpump power lead. Truck started stumbling when getting on freeway. I was like what the hell?? got home and found the culprit. Believe me they are gettin an earfull first thing tomorrow. If my injection pump got hurt from this they will not like it when they eat the bill on that replacement. took a bunch of pictures to prove they never hooked it up again. anyway thanks for the suggestions