You might be saying get new batteries but these are not very old. Let me explain what is happening first. about a year or two back when the temp. was about the low 40 or low 50's I could get in the truck and click the key forward and the wait to start light would take a while but as soon as it would go off the truck would start. but now if I do that it drains the batteries and no start. Now I have replaced the batteries about a year ago and I have taken them out and charged them to full capacity. Now if I plug it in no problems it will start right up like if it was summer. I never have this issue in the summer time. This is the first time I have had this issue I hate to be plugging it in for only 50 degree weather. I am not sure what the issue is I would like some help on this. I have a buddy that has a 2002 and has no issue's with turning it on. so yea like I said on the title HELP please. thank you in advance.

 

Test your batteries. Should be ~ 12.6 volts in the morning if fully charged. If they are good, look for a paracitic drain.

 

I forgot to mention that the truck does not get warm. Even when I have it plugged it the heater never gets warm enough only after like 2 hour's of driving it will it finally get warm. Junk Man I have tested them and one is always charged to 12.6 and the other is in the middle and I have not found a drain of power at all plus if it did have that drain wouldn't it do it during the summer also. But the truck never gets warm. I used to plug her in and when I went down to start her I unplugged her and started right up and after like 5 or 10 min the heater was nice and warm now its not even doing that. Now again in the summer I never have these issue's. I do hear the heater grids come on and off but it acts like they are not doing a very good job heating. Am I suppose to hear them come on when I plug the truck up?

 

have had your starter tested?

 

Get 'em load tested at Napa or an auto parts. You may have a bad cell in one of them, even if new.

 

12.6 is fully charged. Less than that is not. Google for a list of voltage and % discharged. Does starter crank engine at normal speed? My dash volt meter drops to 12 when grid heaters are on. You can measure voltage to see if they are getting current. Can also pull air horn of to examine grid heater. Don't drop anything down manifold but you can start & run (idle) without air horn.

 

First off, what CCA Rating batteries did you get when you replaced your old ones? What is your voltage at the batteries when the truck is running? If they are an alright CCA, I would be getting them load tested. Perhaps also getting the charging system tested as well. Then while you have the clamp on to test in chassis Alternator output...you could use that Amp Clamp to measure how much current your starter is pulling..

Also, if your truck is not getting up to operating temp, I'm going to lean towards your thermostat is stuck open.

 

Thanks guys... I will check all this tomorrow morning. oh the voltage on the batteries when the truck is running is above normal it is always past the middle line. I think middle is 24? It only does it when it is cold outside. I have a new Thermostat I bought earlier but I posted that just to make sure I was on the right track with it. Again thank you

 

If the batteries are the same type and age, when you isolate them from each other they should both be at the same voltage. If they are not, I would have them load tested, and cell tested if possible. It sounds like you may have a defective one.

If the batteries load test and cell test ok, I would reinstall them, verify that the truck is charging ok, then I would hook up an ammeter and check to see if they are being drawn down while the truck is shut off. Keep in mind that if this is a quad cab, the electric seat belt locks will cause a big draw for quite a while after the truck shuts off. You'll need to keep the ammeter hooked up for more than 30 minutes until the seat belt module and everything else has timed out. After that time, your ignition-off draw should be less than 30 milliamps.

 

You may have a bad T-stat also. Get the Cummins one.

 

ok you lost me on the whole T-Stat thing??? I am going to check everything tomorrow. I have started it once today and it seemed fines since I had it plugged in. I'll test everything tomorrow and let yall know.

 

T-Stat is themostat. If you do not use a Cummins or I think, a specific brand, it may not work properly. Do a search on T-stat of Themostat. Your truck should get somewhat warm within 5-10 miles of light driving, fater with a load. If your T-stat is stuck open, it will take forever to warm in cold weather.
It sounds like your batteries are not up to he task. As said before, get them load teastes at your battery store and make sure they have the right Cold cranking amps and reserve.
Also, make sure your battery connections are clean and free of corrosion.
Tests the voltage with the engine running. You should see about 13.8-14V if the Alternator is charging proerly.

 

being a starter& alternator guy both batteries should have same voltage it always takes alittle more amps when cold.Your alternator should put out anywhere from 13.8 to14.6.your alt could have a blown diode but if your truck is auto would scew up your overdrive.Check batt cables take them of and clean and see if they are black inside therminals that will cause a voltage lost good luck

 

ok sorry guys I have not posted in a while. I have been crazy busy. I replaced a battery and it worked. The other battery is good I had one that tested bad. I also changed the thermostat and it worked, started getting warmer faster. At first I got worried because it looked like it was getting to hot before it opened up but it is fine. plus it is winter now so I want it to get warm. Guys again many thanks to all of you guys for you help. I had another question I am trying to research it on this site right now but I might as well ask here. Is it bad to start the truck when it is plugged in? I heard that it was but a guy I met said he starts it all the time and has not had problems with it. I didnt want to believe him.

 

Won't hurt a thing starting it while it's plugged in...........as long as you remember to unplug it before you drive away !!