questionable voltmeter

[pocojo]

Hello fellow Jeepers,
I have a 1998 wrangler TJ 4.0 w/156k mi. This machine runs like a well oiled Swiss sewing machine and everything on it works except the voltmeter, however when I had a battery charger connected to it (because I was doing repairs with the doors open all day) I noticed the volt meter needle was pegged full right. I believe the instrument itself is fongoolerized and was thinking of adding an under dash Stewart Warner meter simply because of the high miles. I like to see in advance when components are failing, not to wait till I see the headlights dimming wondering if Im going to make it home. The meter needle just stays centered at all times.I would appreciate any suggestions or history of anyone experiencing this same problem. Thank you all and I wish you all a happy/safe Labor Day weekend.
Pocojo

 

[Boinked]

First thing run a cluster self test.

 

[Jerry Bransford]

The voltmeter doesn't move vert much like the old ammeters did. It usually registers 12.6 or thereabouts without the engine running and anywhere from 13-something to 14-something depending on the alternator's output which depends on the battery charge.

If the meter jumps to the high-end of the scale, that very commonly indicates nothing more than a dirty, corroded, or loose connector at one of the battery posts. Even if they look ok, my recommendation is to physically remove both connectors, then wire brush the battery posts and the inside of the connectors until they're bright & shiny clean. Then securely reinstall them, tightening the nut securely enough that the connector can't be moved with considerable hand pressure.

After doing that, see if the high voltage indications at the dashboard volt meter don't stop. Replacing or augmenting it with an aftermarket volt meter wouldn't really do much for you, the OE voltmeter works well as is.

The above cluster self-test doesn't really do much other than see if the gauge needles swing up & down which is not really testing anything of consequence like their accuracy.

 

[pocojo]

The voltmeter doesn't move much like the old ammeters did. It usually registers 12.6 or thereabouts without the engine running and anywhere from 13-something to 14-something depending on the alternator's output which depends on the battery charge.

If the meter jumps to the high-end of the scale, that very commonly indicates nothing more than a dirty, corroded, or loose connector at one of the battery posts. Even if they look ok, my recommendation is to physically remove both connectors, then wire brush the battery posts and the inside of the connectors until they're bright & shiny clean. Then securely reinstall them, tightening the nut securely enough that the connector can't be moved with considerable hand pressure.

After doing that, see if the high voltage indications at the dashboard volt meter don't stop. Replacing or augmenting it with an aftermarket volt meter wouldn't really do much for you, the OE voltmeter works well as is.

Thanks brother Jerry, Im a stickler for cleanliness at all electrical connections. I recently went thru all my engine compartment grounds (about 8 of them ), cleaned them shiny and applied koppercte conductive paste to all. I connected a Flukemeter multimeter and it indicates almost 14 volts, thats why I suspect the OEM meter itself is not as sensitive as it should be. Thanks again for replying and again thanks for your service brother.
Pocojo

 

[pocojo]

First thing run a cluster self test.

Thanks much for your reply.I have a 1998 and wish I had that feature.

 

[Boinked]

The above cluster self-test doesn't really do much other than see if the gauge needles swing up & down which is not really testing anything of consequence like their accuracy.

The seft test will make all gauges run full swing. And will detect any faults in the cluster its self. While it wont tell you where your problem is it will tell you your gauges are working. It takes less then a minute. If he had a neddle that was stuck it would show that.
It never hurts to run that check first to eliminate the easiest thing. Before spending time cleaning up and chasing down connections.
While most of the time it won't be that it never hurts to do.

 

[Boinked]

Thanks much for your reply.I have a 1998 and wish I had that feature.

My 97 has it

 

[pocojo]

My 97 has it

This one only has a button that goes from odometer and tripometer

 

[Boinked]

Hold it down with the key off. (Keep it held down the entire time) tirn key to on. Do not start. It will cycle through its test.

 

[pocojo]

The seft test will make all gauges run full swing. And will detect any faults in the cluster its self. While it wont tell you where your problem is it will tell you your gauges are working. It takes less then a minute. If he had a neddle that was stuck it would show that.
It never hurts to run that check first to eliminate the easiest thing. Before spending time cleaning up and chasing down connections.
While most of the time it won't be that it never hurts to do.

Okay Jerry,
Excuse my ignorance, I went to you tube and found the proper procedure for the cluster test. All indicated proper operation and at this point, Im going to let things ride as there are much more important things in life than to worry about a voltmeter. I thank you for always responding and wish you a happy end to summer.
Pocojo

 

[pocojo]

The voltmeter doesn't move vert much like the old ammeters did. It usually registers 12.6 or thereabouts without the engine running and anywhere from 13-something to 14-something depending on the alternator's output which depends on the battery charge.

If the meter jumps to the high-end of the scale, that very commonly indicates nothing more than a dirty, corroded, or loose connector at one of the battery posts. Even if they look ok, my recommendation is to physically remove both connectors, then wire brush the battery posts and the inside of the connectors until they're bright & shiny clean. Then securely reinstall them, tightening the nut securely enough that the connector can't be moved with considerable hand pressure.

After doing that, see if the high voltage indications at the dashboard volt meter don't stop. Replacing or augmenting it with an aftermarket volt meter wouldn't really do much for you, the OE voltmeter works well as is.

The above cluster self-test doesn't really do much other than see if the gauge needles swing up & down which is not really testing anything of consequence like their accuracy.

Hi Jerry,
I greatly respect your knowledge of electricity and would like to thank you for your advice about welding on my Jeep's frame. I followed your recommendations and after many welding applications, I never had a problem. thanks again brother. Now I have another question to ask you, only when its cold and I try to activate the windshield wipers, I get nothing. Wiper blades are not frozen to the glass, fuse is not open, but after four or five engine shutdowns and restarts, they will operate properly. To my limited knowledge I don't think the wipers are dependent on the ECM, but again I state my knowledge is limited in this area. I would appreciate any theory you may have on this issue. Thanks Jerry and thanks for your service brother.

Pocojo

 

[tworley]

Sounds like your wiper motor is on the fritz. Pretty easy fix
https://wranglertjforum.com/threads/front-wiper-motor-replacement.226/

 

[Jerry Bransford]

Sounds like your wiper motor is on the fritz. Pretty easy fix
https://wranglertjforum.com/threads/front-wiper-motor-replacement.226/

That or perhaps the wiper switch contacts are going bad. It's doubtful to be anything else, and the PCM has no direct control over the wipers.