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Topic Review (Newest First)
November 11th, 2019 04:42 PM
CWhiteRun
Quote:
Originally Posted by daaam View Post
I must be doing something wrong because when I try to measure resistance it just shows all zero's. I see it calculate each time I connect the wires but it shows zero's. I tried checking resistance on the wire itself and also on the post of alternator with wire hooked up and battery post under hood, but it just shows zero's.

I did hook up a new sense wire from my fuse box and it seems to be working decently but I won't know for sure until I can actually road test it, which I won't be able to do until spring as it is snowing here now.

Thanks everyone for your help. I hope replacing the sense wire works.
"0.0" on your meters display is better than "--" when measuring resistance. Any numerical value shown means that there is connectivity between the two points of the wire. The higher the numerical value that is displayed then the more resistance the wire has which means that current doesn't travel as easily through the wire.
Whenever you get more time to play with it post your findings up.
November 10th, 2019 09:50 PM
daaam I must be doing something wrong because when I try to measure resistance it just shows all zero's. I see it calculate each time I connect the wires but it shows zero's. I tried checking resistance on the wire itself and also on the post of alternator with wire hooked up and battery post under hood, but it just shows zero's.

I did hook up a new sense wire from my fuse box and it seems to be working decently but I won't know for sure until I can actually road test it, which I won't be able to do until spring as it is snowing here now.

Thanks everyone for your help. I hope replacing the sense wire works.
November 9th, 2019 10:24 PM
jslimm
Quote:
Originally Posted by CWhiteRun View Post
You can disconnect the cable from the stud if you'd like to take the reading.
Just be very cautious removing the nut from the stud if it has never been removed before. Make sure that the stud does not turn !!! Quite a few people have had to contend with a loosened stud, and the intermittent that causes and the hassle to fix it.
November 9th, 2019 08:03 PM
CWhiteRun
Quote:
Originally Posted by daaam View Post
Instead of insulting me, you could have just told me how to check resistance. I like to work on my own vehicle's and I come here for help on fixing my problems.
Didn't insult you at all and I instructed you to take a resistance measurement to help you get started with figuring out your problem Now that you know how to do that....If you would...measure resistance from the back of the alternator to the stud on the fuse block under your hood. You can disconnect the cable from the stud if you'd like to take the reading. If you're running an alternator that's no longer being regulated by the ECU then you need to ensure that the engine block to battery/chassis ground connection is good other wise the regulator will not function correctly. You can measure resistance from the engine block to the negative battery terminal as well and also post that reading here.
November 9th, 2019 08:01 PM
CWhiteRun Edit: duplicate post
November 9th, 2019 10:10 AM
daaam
Quote:
Originally Posted by jslimm View Post
You can't check resistance when there is a voltage applied to the thing you are checking.(well, not totally correct; but, you have to know what you are doing)
There has to be no voltage applied so that no current is running through it. Typically you would want at least one of the endpoints disconnected so that you are not measuring the resistance of more things in the circuit than you intend to measure (and that also ensures that no current is flowing in the thing you are measuring.)
Ok. I will check resistance with wire cold and then when its hot. I will disconnect the wire prior to testing it.
November 8th, 2019 07:06 PM
jslimm
Quote:
Originally Posted by daaam View Post
Thanks so much! I will try this, this weekend. I assume I will have to do this when the wire is cold. Then check when the wire is hot, and check when car is running?
You can't check resistance when there is a voltage applied to the thing you are checking.(well, not totally correct; but, you have to know what you are doing)
There has to be no voltage applied so that no current is running through it. Typically you would want at least one of the endpoints disconnected so that you are not measuring the resistance of more things in the circuit than you intend to measure (and that also ensures that no current is flowing in the thing you are measuring.)
November 8th, 2019 09:53 AM
daaam
Quote:
Originally Posted by AJ02 View Post
To measure resistance, all you have to do is set your multi-meter on one of the settings with the symbol that looks like a modified horseshoe. ( OHMS ) Measure from one end of a wire or circuit to the other and the reading will be the amount of resistance.
Thanks so much! I will try this, this weekend. I assume I will have to do this when the wire is cold. Then check when the wire is hot, and check when car is running?
November 6th, 2019 04:35 PM
AJ02 To measure resistance, all you have to do is set your multi-meter on one of the settings with the symbol that looks like a modified horseshoe. ( OHMS ) Measure from one end of a wire or circuit to the other and the reading will be the amount of resistance.
November 5th, 2019 04:31 PM
daaam
Quote:
Originally Posted by RobV View Post
what are you using to measure voltage?
2 separate digital multi meters. I use two to verify that my results I am measuring are accurate. The results always seem to be within .01 volts of each other so I am assuming they are accurate, and it reflects similar on my voltage gauge in my car (i don't rely on the car gauge as it seems to read slightly lower than my multi meters and its not precise enough)
November 5th, 2019 04:27 PM
daaam
Quote:
Originally Posted by CWhiteRun View Post
Don't take this the wrong way but if you do not know how to measure resistance then you really don't need to mess with the cars electrical system and you really should pay someone to troubleshoot for you. Also, the field control wire on the viper harness is not the field control wire on the alternator that viper uses.....it's done odd on viper. It would be in your best interest to tote it to a specialist.
What is the worst thing that happens if I don't measure resistance?????? Is my car going to blow up? am I going to get electrocuted and die? Nope, none of that. I would just be chasing my tail a little bit more and possibly trying things that may not need to be done, but does it really hurt anything? You really think that not being able to measure resistance is that imperative that I can't attempt to troubleshoot an electrical problem? I have troubleshooted every single electrical issue I have had for the last 20 years with no problems. This is actually the first time that I have struggled with a 12v electrical issue which is why I brought it up on the forums.

Most people are not experts and can work on things adequately, correctly and safely and this includes troubleshooting issues with my cars electrical system. I have above the basic understanding of how to wire 12 volt sources and have been doing it for over 20 years with zero issues thus far (I have had zero problems from my troubleshooting so far and I may have even figured out the issue). If I am getting the exact same results with brand new, larger wire of similar length that is directly wired from alternator to the battery without heat soak being an issue then resistance in that wire is not the issue and I can rule out that wire being an issue. I believe I would kind of be measuring resistance by checking the voltage output on alternator post compared to output showing at the battery and at the 12v post under hood? The larger the voltage drop the more resistance that may be being created?

It also just so happens that I did go to a professional and explained every test I did and they literally told me that is exactly what they would have done (but I guess I should have paid them $80.00 - $100.00 an hour to do the same tests) and then learn nothing in the process? They are very stumped as well on the issue and all they do for a living is electrical work dealing specifically with starters, alternators, etc...

I have the shop manuals that a technician would use for my car, I know which wires does what as it is outlined in the shop manual. My alternator has an internal regulator which is different from the gen 2's which are controlled by the PCM. I knew which wire was my sense wire by looking at the shop manual. I do appreciate you bringing up the issue with how the field wire is different on a Viper as that is the input I am looking for, not told to just bring it somewhere because you know how to check resistance and I don't. Now if I could get killed by not checking resistance you may be right to refer me to a professional.

Instead of insulting me, you could have just told me how to check resistance. I like to work on my own vehicle's and I come here for help on fixing my problems. I can't think of how useless forums would be if everyone's answer was to take something to the shop, as lots of people learn on the forums by doing things that they haven't done before. If I wanted to bring my car to someone to fix I would but I would rather learn and save my money.

Electrical issues are actually probably one of the last things you want to take to a shop as they can be some of the most costly repairs as the troubleshooting can be extensive, taking a lot of time to find the issue which transfers to being very expensive.
November 5th, 2019 09:53 AM
CWhiteRun Don't take this the wrong way but if you do not know how to measure resistance then you really don't need to mess with the cars electrical system and you really should pay someone to troubleshoot for you. Also, the field control wire on the viper harness is not the field control wire on the alternator that viper uses.....it's done odd on viper. It would be in your best interest to tote it to a specialist.
November 4th, 2019 07:38 PM
RobV
Quote:
Originally Posted by daaam View Post
I don't know how to measure the resistance....
what are you using to measure voltage?
November 4th, 2019 03:18 PM
Lunchbox
Quote:
Originally Posted by daaam View Post
The 96RT-10's don't have the battery temp sensor. Thanks for the thought.
My bad, wasnt aware.
November 4th, 2019 01:40 PM
daaam
Quote:
Originally Posted by 99RT10>S View Post
I assume you cleaned/sanded the ground point good? There is another ground behind the front left wheel too. Clean it off and re-attach
I have cleaned and cleaned and cleaned, LOL. I didn't see that ground as the only one I seen was the one on passenger side that connects kind of by the passenger side front wheel to the front of the engine block.
November 4th, 2019 01:37 PM
99RT10&GTS
Quote:
Originally Posted by daaam View Post
This was disconnected and I reconnected it but I still had the same problem except when first starting up car it charges at 14.55 instead of 14.3 volts and drops from that point like before.
I assume you cleaned/sanded the ground point good? There is another ground behind the front left wheel too. Clean it off and re-attach
November 4th, 2019 01:08 PM
daaam
Quote:
Originally Posted by 99RT10>S View Post
Check the ground strap near the front right side of the engine. If it is loose or disconnected, it could be causing the problem. I have heard it can cause problems with the oil cooler lines too.
This was disconnected and I reconnected it but I still had the same problem except when first starting up car it charges at 14.55 instead of 14.3 volts and drops from that point like before.
November 4th, 2019 01:07 PM
daaam
Quote:
Originally Posted by CWhiteRun View Post
Remove the pin from the ECU connector that is responsible for field control. Also, measure resistance from the back of the alternator to the post on the front of the under hood fuse block and post it here.
I don't know how to measure the resistance. I did run a power wire from the fusebox and hooked it up to the sense wire on the alternator and at idle (when hot) the alternator is at under 13 volts (just like with factory wire hooked up) but with any rpm given (even 100rpm) then it jumps back up to 14.3 volts at the alternator post. I have a .2 volt drop from the alternator post to my battery which I think is acceptable (that .2 volts drop has been consistent with all my tests I have done). I am thinking that somehow the sense wire may be bad.

I literally bought zero gauge wire and ran it right from the alternator to the battery and the same issue occurs when alternator is hot. The only thing that has changed anything is me changing to the sense wire to a 12 volt source from the fuse box. I still feel like the alternator never got so low at idle in the past when i had no issues, but owners manual says to test alternator at 1500 rpm and then I do that it is charging at 14.3 volts. It is just weird that at idle when the car is cold that it charges at 14.55 volts but as it heat soaks it goes so low.

I am just going to replace the sense wire for now and try it next spring to see if this solves my issue. If not I will be back but I am not sure what else I can do as I tried zero gauge right from alternator to battery, zero gauge from alternator to power post under hood then right to battery. I replace grounds on vehicle and to battery with zero gauge wire. I tried hooking zero gauge wire directly from battery negative terminal to the alternator, and everything I do I get the same results except for the sense wire. I did almost every combination of connecting wires that I could think of and even at the alternator the charging level drops.
November 4th, 2019 01:04 PM
daaam
Quote:
Originally Posted by Lunchbox View Post
Have you checked the battery temp sensor? If you've gone through alternators, starters and ground wires, this might be something to check in addition.
The 96RT-10's don't have the battery temp sensor. Thanks for the thought.
November 4th, 2019 12:29 PM
Lunchbox Have you checked the battery temp sensor? If you've gone through alternators, starters and ground wires, this might be something to check in addition.
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