How to test a coil with a voltage meter - 1987 Dodge Ram 50

The power supply is direct from the battery so the voltage supply to the relay should be between 12 and 14 volts. Most relays have a voltage rating marked on them as a 'VDC' number.

You'd need a multimeter and set it to Ohms to test for resistance of the coil, also put it to Ac mode and if it's an old style analog meter the needle should move. On a digital meter you'll see if the voltage rises. Make sure you choose AC settings, preferably an auto ranging meter, mines Fluke meter.

With a Volt Ohm meter.
The pick up coil should produce a low AC voltage when the distributor shaft turns as in cranking the engine.

Inspect/Test/Replace Hope this helps.

An ignition switch supplies voltage to the ignition control module and/or the ignition coil. Often an ignition sytem thas two wires connected to the run terminal of the ignition switch. On is connected to the module. The other is connected to the primary resistor and coil. The start terminal of the switch is also wired to the module.
You can check for voltage using either a 12-volt test light or a digital multimeter (dmm).
To use a test light:

• Turn the ignition key off and disconnect the wire connector at the module.
• Disconnect the S terminal of the starter solenoid to prevent the engine from cranking when the ignition is in the run position.
• Turn the key to the run position and probe the red wire connection to check for voltage.
• Check for voltage at the battery terminal of the ignition coil using the test light.
• Next, turn the key to the start position and check for voltage at the white wire connector at the module and the battery terminal of the ignition coil. If voltage is present, the switch and its circuit are okay.

To do the same test using a DMM:

• Turn the ignition switch to the off position and back-probe, with the meter's positive lead, the power feed wire at the module.
• Connect the meter's negative to a good ground at the distributor base.
• Turn the ignition to the run or start position as needed, and measure the voltage.
• The reading should be at least 90% of battery voltage.

Have a repair shop use the proper test
equipment, to resolve the issues.

Codes do not always point you to the bad coil

Your checking primary voltage at coil (Battery Voltage)

Continuity is not for a component under power
Lucky you didn't load the PCM Drivers and ruin it

If your going to current ramp a coils primary vs
look at the secondary,you need an oscilloscope.

Using a volt meter disconnect the electrical plug to coil and check with key on to be sure there is at least 12 volt to coils. if not or voltage is low the ignition switch may be bad, have an assistant jiggle the key in ignition while you are looking at the meter to note voltage fluctuations if any are noted ign. switch is bad also check all fuses under dash as wellas in engine compartment.

Unplug the spark plug wires from the coil and label the wires if necessary for proper installation.

4 Unplug the pack's electrical connector and remove the coil pack from the engine, using a wrench or ratchet and socket if necessary. If your coil pack is mounted on the back of the engine, raise the front of the vehicle and safely support it on two jack stands to reach the coil pack from underneath the engine.

5 Set your ohmmeter to the 20000 ohms range. Turn on your meter and touch the spark plug wire terminals on one of the coils with the meter leads. You may get a reading between 5000 to 15000 ohms, depending on your particular model. This checks the secondary resistance.

6 Set your ohmmeter to the 10 ohms range, and touch the terminal B+ (usually the center prong on the coil pack electrical connector) with one of the meter test leads, and touch the corresponding coil prong on the electrical connector with the other test lead. You may get a reading between 0.3 and 1.0 or more, depending on your particular model. This checks the primary resistance on each coil.

7 Repeat steps 6 and 7 for each coil in the pack assembly, and compare your resistance readings to the specifications given on your vehicle service manual (see "Tips"). If your readings are out of range, replace the coil or coils as necessary.

Read more: How to Check Coil Packs With a Voltage Meter ' eHow.com http://www.ehow.com/how_4912368_check-coil-packs-voltage-meter.html#ixzz13fJECvLx

The coil is tested with a volt ohm meter set the meter to 200 on the OHM setting and see if you get 18,000 ohms or better. If not it is a weak coil

start at the coil with dvom or test light to see if there is power to the coil when you turn the key on and the power should be there during cranking the best way is the dvom when you check battery voltage with digital volt meter at the battery record that amount then check the red wire at the coil should be 0.50 volts within battery recorded voltage if its allot less check voltage at ign switch should read real close to battery voltage this is called battery voltage drop testing if you google voltage drop testing it will exsplain further. i hope this helps Thunderboltz.

P1370 Ignition Control (IC) Module 4x Reference too many pulses

P1350 Ignition Control System

Ok, these codes are signaling a malfunction within the Ignition control module. it is sending way to many signals to the coil. i recommend testing the coil for damage and irregular resistance. i will explain how to do this below. i would replace the module as well. The control moduel is Located Under hood, center, rear engine area, above valve cover, mounted in base of ignition coil pack

Ignition Coil Test Procedures__

Ignition Coil Resistance

* with the key off and the battery lead to the ignition coil disconnected, use an Ohmmeter to measure the primary and secondary winding resistance of the ignition coil. when checking the resistance across the windings, pay particular attention to the meter reading. if the reading is out of specifications, even if it is only slightly out, the coil or coil assembly should be replaced.
* To check the primary windings, calibrate an ohmmeter on the X1 scale and connect the meter leads to the primary coil terminals to test the winding.



* An infinite ohmmeter reading indicates an open winding. The winding is shorted if the meter reading is below the specified resistance. Most primary windings have a resistance of 0.5 to 2 ohms, but the exact manufacturer's specifications must be compared to the meter readings.
* To check the secondary winding, calibrate the meter on the X1,000 scale and connect it from the coil's secondary terminal to one of the primary terminals.



# A meter reading below the specified resistance indicates a shorted secondary winding. An infinite meter reading proves that the winding is open.
# In some coils, the secondary winding is connected from the secondary terminal to the coil frame. When the secondary winding is tested in these coils, the ohmmeter must be connected from the secondary coil terminal to the coil frame or to the ground wire terminal extending from the coil frame. Many secondary windings have 8,000 to 20,000 ohms resistance, but the meter readings must be compared to the manufacturer's specifications. The ohmmeter tests do not indicate such defects as defective insulation around the coil windings, which causes high-voltage leaks.