Hard Starting:
* Crankshaft Position Sensor (CKP): A failing CKP sensor is a common cause of hard starting issues in many vehicles, including Dodge Rams. It tells the engine's computer where the crankshaft is, allowing for proper ignition timing. A failing sensor can lead to inconsistent starting or no starting at all.
* Cam Position Sensor (CMP): Similar to the CKP, a faulty CMP sensor affects ignition timing and can cause hard starting.
* Battery/Alternator: A weak battery or alternator won't provide enough power to crank the engine properly. Test the battery voltage (should be around 12.6V when not charging, and above 13.5V when running) and the alternator's output.
* Ignition Switch: A failing ignition switch might not be providing sufficient power to the starter motor.
* Starter Motor: The starter itself could be failing, requiring excessive cranking or not engaging properly.
* Fuel System: A clogged fuel filter, weak fuel pump, or issues with the fuel injectors could prevent sufficient fuel delivery to the engine.
Weak Heater:
* Low Refrigerant: The most likely cause of a weak heater is low refrigerant in the AC system. A leak somewhere in the system would cause this. This is *especially* suspect given that it's a 1999 vehicle. AC systems lose refrigerant over time.
* Blend Door Actuator: This small motor controls the airflow direction (hot/cold). A malfunctioning actuator might not be directing enough hot air into the cabin.
* Heater Core: A clogged or partially blocked heater core restricts hot coolant flow, resulting in weak heat. This is less likely given that the heater worked at some point.
* Thermostat: A stuck closed thermostat would prevent coolant from circulating properly, reducing the heat output. But this would usually mean the engine is also overheating.
Possible Correlation:
The most likely reason the two problems are connected is the battery/alternator. A weak battery could struggle to provide enough power for starting *and* the AC compressor, resulting in weak heating/cooling. A failing alternator may not be charging the battery properly, leading to the same problem.
Troubleshooting Steps:
1. Battery and Alternator Test: This is the most crucial first step. Get your battery and alternator tested at an auto parts store; it's a free service.
2. Check Engine Light: If there's a check engine light on, have the codes read (again, auto parts stores usually do this for free). This could pinpoint issues with sensors or other components.
3. Refrigerant Level (AC): Have an AC professional check the refrigerant level in your system. Low refrigerant is the most probable cause of the weak heater issue.
4. Inspect Wiring and Connections: Look for any loose, corroded, or damaged wiring, particularly around the starter motor, sensors, and the heater system.
If you're not comfortable with automotive repairs, take your truck to a qualified mechanic. They can diagnose the problem more accurately and perform the necessary repairs. Starting with the battery/alternator test is your best bet.
