COIL 12 VOLTS DODGE
INSTALLATION INSTRUCTIONS
COILS FOR 12-VOLT SYSTEMS
RESISTOR NOT REQUIRED
1. DO NOT INSTALL these coils on 12-volt systems equipped with a resistor or with resistance built into the wiring harness.
2. SELECT THE RIGHT COIL by referring to the application guide in the catalog.
3. COIL POLARITY MUST BE CORRECT. If the negative battery post is grounded, the coil terminal
marked (-) must be connected to the distributor. If the positive post is grounded, connect the coil marked (+) to the distributor.
4. All connections must be clean and tight. Make sure the coil high tension wire is firmly seated in the coil tower and the spark plug wires are firmly seated in the distributor cap towers
🔧 How to test a 12V ignition coil for a classic car (technical explanation)
📋 Tools required:
-
Multimeter (set to Ohms (Ω))
-
Coil disconnected or removed from vehicle
-
Optional: screwdriver
⚡ STEP 1: Measure the primary circuit (low voltage)
Test points: between + and - (sometimes marked “15” and “1”)
🔌 Procedure:
-
Set multimeter to Ω.
-
Measure between + and - terminals.
-
A proper value for a 12V coil is 2.5 Ω to 4.5 Ω.
📎 Explanation:
This is the resistance of the primary winding. Too low = short circuit, infinite or very high = open winding.
⚡ STEP 2: Measure the secondary circuit (high voltage)
Test points: between the central high-voltage output (spark plug cable) and one of the terminals (+ or -)
🔌 Procedure:
-
One probe on the central output.
-
One probe on the “-” terminal.
-
Expected value: 6,000 Ω to 15,000 Ω.
📎 Explanation:
This checks the high-voltage winding. Too high or no value = defective winding or internal fault.
⚡ STEP 3: Spark test (optional)
-
Connect a spark plug to the center output.
-
Hold it against ground (engine block).
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Turn ignition on, briefly tap “-” to ground.
-
A strong blue spark should appear.
🔍 No spark = faulty coil or poor contact.
📌 Summary of typical values
| Test | Where to measure | Expected value |
|---|---|---|
| Primary | between + and - | 2.5 – 4.5 Ω |
| Secondary | center to - terminal | 6,000 – 15,000 Ω |
| Spark | visual test | strong blue spark |
🧠 Common issues
| Problem | Possible Cause |
|---|---|
| No spark | Primary open, bad ground |
| Weak spark | Poor ground, internal defect |
| Coil gets hot | Low resistance, incorrect coil used |