I have a 99 Ram 1500 that I don’t drive too often. With the cold temperatures the battery died so I jumped it, no problem. Now the heater won’t blow hot and there’s no output to the speakers, although the radio seems to be working as normal.

Any suggestions?

 

What else doesn't work?

 

That’s all I’ve noticed so far. The air will still change vents from defrost to floor etc. Radio switches frequencies and modes. The lights work, truck runs and sounds fine. The power locks seemed really slow and weak working, however.

 

Is the alternator charging the battery?

 

I turned the truck off several times, let it sit, and was able to start it again. It seemed weak. Possibly the battery is going? It reads ok on the dash.

 

You need to either take a long road trip or use battery charger. If you jumped it, it had a weak charge and running engine only a short period of time will not be enough.

 

If you don't have one, get a digital volt/ohm meter. These have a lot of uses so it won't be wasted money. Use it to check your battery at rest. It should read around 12.5, more or slightly less. Now check it with the engine running. It should be reading 13.4 or more. Possibly as high as 15 volts. You may not have much amperage reserve. It takes a while to build it up fully. Now, if the battery was discharged for a long time, it may have lost its reserve ability. Basically, it died. I've gotten them going by being on a charger for extended periods of time, and I've seen fully charged and HOT batteries lose their charge over night. If that happens, don't fight it, just replace the battery.

 

Thank you. I do have one and I’ll give it a shot!

 

When you measure the battery, be sure that the cable clamps are clean and tight to the battery post.
I went to start my Jeep ZJ couple of days ago, starter solenoid engaged and nothing. Lost all the power. Went to check the ground cable because I just push and twisted it in place (Jeeps been just sitting and waiting for me to fix it so I take the cable of to keep battery charged). Cable was tight, so was the positive cable. What the heck... Got the multimeter and verified that I have over 12 volts on posts. Thought that I burned fusible link, but whole vehicle was dead. Then I measured from positive post and negative clamp, still over 12 volts. But when I measured from negative post to positive clamp, I got only 6 volts. Took the positive clamp off, didn't even cleaned it just mounted it back and got the engine running.

 

I bought a new battery and the radio and heater still aren’t functioning. Does anyone know a good thread for diagnosing heater issues?