Fix It

Problems that occur within an auto electrical system cant be dealt with until you determine whats causing the problems and why. However, with a little information and a few easy-to-use tools such as a voltmeter, nearly anyone can diagnose electrical issues common with some of todays automobiles.

Diagnose Voltage

Voltage problems within an auto electrical system are often caused by loose connections in the wiring. A bad ground connection or a faulty switch could also be the culprit. Doing a voltage drop test using a voltmeter will allow you to check for a drop in voltage, which indicates trouble if the drop is greater than 0.4 volts.

Diagnose Circuits

Because all circuits have to have voltage to power products, the first thing to do when diagnosing circuit issues in an auto electrical system is to check for voltage at the head of the circuit. No voltage here indicates problems with areas that supply the circuit with voltage, such as the power relay.

Diagnose Circuit Breakers

A test can be done to help determine if a circuit breaker has gone bad. By bypassing the circuit breaker using a jumper wire, it can then be attached directly to the circuit in order to test it. If the circuit is found to be in working order after bypassing the circuit breaker, then the circuit breaker is the problem and will have to be replaced.

Harley-Davidson refers to the electrical control module (ECM) as being plugged into the "electrical caddy." The location of the electrical caddy, however, varies according to motorcycle model. On V-Rods and Buells, the caddy is under the rear seat; Rockers and Night Trains require you to remove the rear fender to access the ECM. On most Harleys, the caddy is on the right side of the motorcycle, approximately under the seat. Check your owners manual if you are unsure where the electrical caddy is on your motorcycle. This procedure works for all Harley Dynas and Wide Glides.

Instructions

1

Loosen and remove the bolt and washer on the rear tab of the motorcycle seat using an Allen wrench. Remove the seat by pulling up and back.

2

Disconnect the negative (black) battery terminal using a box wrench.

3

Remove the electrical caddy cover by firmly grasping both sides and pulling outward.

4

Insert a small screwdriver into the slot under each relay/fuse panel to disengage it. Insert two small screwdrivers into the slots on each side of the main fuse. Depress the tabs of the main fuse connector with the screwdrivers and remove the main fuse.

5

Depress the tab that secures the Turn Signal Module/Turn Signal Security Module (TSM/TSSM). Pull the TSM/TSSM from the electrical caddy and disconnect.

6

Disengage the data link connector by sliding it toward the front of the motorcycle.

7

Disconnect the electronic control connector. Remove the ECM.