# '95 D21 strange lights this morning



## FriPilot (Sep 3, 2010)

Folks, this came out of the blue this morning. On the way to work, both my parking brake light and my battery light began flickering, then stayed on solid. If I disengaged the clutch and freewheeled a bit, the lights would go out. They came back on when the clutch was re engaged. (interestingly, the lights flickered, came on/went off in unison)
While this was happening, the truck ran flawlessly, though it was low on fuel. I refueled and the lights were still on. (guess it's not some cryptic low fuel indication?) 
On my break at work, I started the truck fine, but the lights were still on. Wiggled the POS battery connector, then checked the lights again. They were now out (Yay!) Left work some hours later and they were back on. Truck still running fine. When I got home, I cleaned the battery terminals and connectors and made sure everything was tight. Now the lights don't come on. Took her for a short drive, made a stop, restarted her and drove home. Still no lights on. I have my fingers crossed.
My best guess is that there was a cruddy battery connection, but wonder if any of you have any thoughts.

Thanks

Fri


----------



## GeoBMX4Life (Mar 25, 2010)

Thats exactly what happened. Its a type of ground fault, with the posts clean, you shouldn't have the same problem again.


----------



## FriPilot (Sep 3, 2010)

Thanks for your input, Geo. I'll keep my eye on her and will probably replace those connectors this week. They don't look new, by any means.


Fri


----------



## zanegrey (Dec 5, 2005)

i was getting ready to cheese and crackers this post...


----------



## FriPilot (Sep 3, 2010)

Well, it looks like a continuing saga. Still had the lights coming on this morning and on the way home from work. Went to the parts store for new battery connectors. Left the store and the truck would not turn over at all. Called AAA who sent a battery guy. He determined that the battery needed to be replaced. Voltage was OK, cold cranking amps way below par, it is 3 years old and the battery was way too small for the truck. Bought and had installed a new super duper AAA battery. (Did not replace the battery terminal yet) 
Truck started right up several times. Left the parts store for home and noticed that the brake and battery lights were still on but just flickering more than staying on solid as they had been. Dang! 
Discovered that they would go out right at about 69 or 70 MPH (right around 3K RPM) They came back on when I dropped speed/RPM's. When I got to my turn off, I had to stop and wait for traffic. The lights went out and did not come back on during the remaining 4 blocks home (2nd gear, driving slowly) 
So, I don't know what to think. Maybe the lights were flickering as the new battery came up to full charge? Still a marginal connection somewhere?
My truck is possessed? I'll appreciate any further suggestions.

Thanks,

Fri


----------



## FriPilot (Sep 3, 2010)

"cheese and crackers"?


----------



## dvdswanson (Nov 6, 2005)

have your alt tested. the regulator is probably going bad. the 2 lights are usually a sign that its not charging the battery, which a poor connection could cause as well.


----------



## GeoBMX4Life (Mar 25, 2010)

DVD is correct, but if you want to test your alternator, start the truck and pull the positive clamp off of your battery...if the truck starts to die, your alternator is bad. Its an easy test, and pretty easy to replace.


----------



## SPEEDO (Jun 9, 2003)

^ have to agree with the above posts....


----------



## FriPilot (Sep 3, 2010)

Thanks guys, I tried Geo's suggestion of removing the positive battery connector while the truck was running. The truck died immediately. I guess that's pretty conclusive. I have an appointment with my mechanic for Monday morning. I'll pick up an alternator, let my mechanic do whatever tests she wants to do and, presumably, install the new alternator. I'll post back to let you know the outcome, but I imagine that we already know what that will be. 

Fri


----------



## GeoBMX4Life (Mar 25, 2010)

*Don't pay someone to do an EASY fix *



FriPilot said:


> Thanks guys, I tried Geo's suggestion of removing the positive battery connector while the truck was running. The truck died immediately. I guess that's pretty conclusive. I have an appointment with my mechanic for Monday morning. I'll pick up an alternator, let my mechanic do whatever tests she wants to do and, presumably, install the new alternator. I'll post back to let you know the outcome, but I imagine that we already know what that will be.
> 
> Fri


 Changing the alternator is one of the EASIEST things to do, it'll save you at least 50$ and is a good way to start learning!!!


----------



## smj999smj (Jan 1, 2006)

GeoBMX4Life said:


> DVD is correct, but if you want to test your alternator, start the truck and pull the positive clamp off of your battery...if the truck starts to die, your alternator is bad. Its an easy test, and pretty easy to replace.


This is bad advice for a computer controlled vehicle. This is a test that was used back in the day before cars used computers. Doing this on a computer controlled vehicle can create an electrical surge that can not only damage your ECM, but other computers on the vehicle, as well. The proper way to test an alternator is to first check your cables, connections and battery. If all that is good, a voltmeter can be used to check the charging system. There are a number of articles on the web that tell explain how to check a charging system. Google it!


----------



## GeoBMX4Life (Mar 25, 2010)

smj999smj said:


> This is bad advice for a computer controlled vehicle. This is a test that was used back in the day before cars used computers. Doing this on a computer controlled vehicle can create an electrical surge that can not only damage your ECM, but other computers on the vehicle, as well. The proper way to test an alternator is to first check your cables, connections and battery. If all that is good, a voltmeter can be used to check the charging system. There are a number of articles on the web that tell explain how to check a charging system. Google it!


 With all due respect, 95 and lower DO NOT have the intricate cpu systems that you are talking about. I have yet to come across an HB that has had problems due to testing the alt this way.


----------



## FriPilot (Sep 3, 2010)

Well fellas, the alternator was definitely gone. The bearings were shot and very loud and of course, it failed the bench test. 
A new one was installed this morning. It's quiet and actually charges! 
She's a happy truck.

BTW, I picked up a digital multimeter the other day. Prior to replacing the old alternator, I checked battery voltage with the truck not running. It was about 12.3. 
With the truck running, the voltage dropped noticeably. Digital meters are sure the way to go. My old meter movement style just couldn't differentiate between a volt or two on a 20 volt full scale range.

For what it's worth, my mechanic agrees with SMJ999SMJ. She was appalled to hear that I had tried the battery terminal removal test. She thinks that the fuse link would have caught a surge, but warns against that test. 

Thanks to all for your good advice. I'll be hangin' around trying to learn more.

Fri


----------



## Carruban (Sep 6, 2010)

Yeah don't be testing your charging system like that...stick a voltmeter to the positive terminal on the alternator and then stick the other end to a ground (engine block for example)..there's really no excuse not to do it properly, it's easy. And if your alternator volts are good then check the volts on your battery with the meter, should be 13-14 for alternator and battery (while running). If alternator is not putting out 13-14 it's bad, if it is, but the battery is not getting 13-14 while running you likely have a bad ground or connection. Glad you fixed it, consider buying a chiltons manual for 25 dollars and do these simpler projects yourself, it saves a lot of money and it gives a nice sense of accomplishment


----------



## smj999smj (Jan 1, 2006)

GeoBMX4Life said:


> With all due respect, 95 and lower DO NOT have the intricate cpu systems that you are talking about. I have yet to come across an HB that has had problems due to testing the alt this way.


With all do respect, I've started working for Nissan as a tech in 1985 and even back then they were telling us not to remove the battery cable while the vehicle is running to avoid surges that could be detrimental to the ECU. Maybe you know better than the instructors at the Nissan Northeast Region Training facility, though. Any electrical surge can be detrimental to an electronic control unit. If you'd rather take the chance of ruining a $600 ECM rather than purchase a cheap multimeter and do it the correct way, then that's on your dime!


----------



## GeoBMX4Life (Mar 25, 2010)

*My bad.*



smj999smj said:


> With all do respect, I've started working for Nissan as a tech in 1985 and even back then they were telling us not to remove the battery cable while the vehicle is running to avoid surges that could be detrimental to the ECU. Maybe you know better than the instructors at the Nissan Northeast Region Training facility, though. Any electrical surge can be detrimental to an electronic control unit. If you'd rather take the chance of ruining a $600 ECM rather than purchase a cheap multimeter and do it the correct way, then that's on your dime!


 I stand corrected, a mechanic friend of mine explained it to me. I guess I've been lucky. I was under the impression the worst that could happen was burning a fuseable link. No disrespect intended. Metering the alternator is the only way I will check, or recommend checking an alternator from now on.


----------

