Turn Signal Troubleshooting
by: Bashan - Oct 26, 2011 14:45:39 GMT -6
fototaker and kaaarl like this
Post by Bashan on Oct 26, 2011 14:45:39 GMT -6
A few weeks ago we had a member with some significant turn signal problems and I realized we didn't have anything in the Library to cover that. My good pal Will aka shalom72c suggested that I write something up and he'd create a PDF for the tech section. Rich
Turn Signal Trouble Shooting
Turn signal malfunctions usually occur in one of three ways. I will cover each of these in chapters and you can jump down to your particular problem. The last chapter will be on using a multimeter and wire testing. The scooter I will use as an example is a 2008 Bashan Racer which is a typical Chinese scooter. However, scooters can vary significantly and your wire colors and components may be different. Use this tutorial as a general guide to help you solve your problem.
Chapter One: Turn signal blinks too fast
- This usually means that you have a bad blinker bulb, corroded socket, or bad wire.
- Inspect the turn signals while they are blinking and see which one is out.
- Remove the bulb, inspect the filament, and replace if broken:
- If the filament is good check for corrosion in the socket. Clean with a wire brush, install the bulb, and try the signal. If it still blinks too rapidly jump to chapter four to test the wires. Chapter Two: Signal bulbs light up but do not blink.
- This means you have a bad flasher relay and it must be replaced.
- To get to the flasher on this scooter the front upper cowling must be removed:
- The flasher on this scooter sits in a cup in front of the dash. Although this is a common location members have reported finding the flasher by the battery, rectifier, or on a side frame rail:
- Unhook the flasher from it's connector and take it down to the auto store for a replacement. You can also order one from an online parts vendor.Chapter Three: Turn switch is activated but nothing happens
- This can mean no electricity is getting to the flasher from the black wire, the flasher is bad and stuck in the open position, the flasher ground is bad, the turn signal switch is bad, or there's bad wires. Here is a picture of a common three wire flasher with the inside exposed and a short explanation of how it works:
- Refer to chapter four and check the continuity of the flasher ground wire. If there is no continuity you must trace the ground wire and find the break. The flasher cannot function without a ground.
- Refer to chapter four and test the voltage getting to the flasher on the black wire. If no electricity is getting to the flasher you must trace the black wire and look for breaks or shorts.
- If you have 12v DC at the black wire refer to chapter four and test the voltage on the flasher grey wire. If the grey has no voltage the flasher is bad and must be replaced. Take the flasher to the auto store to find a replacement or use an online vendor.
- If you have voltage at the grey wire refer to chapter four and test the turn switch. If the switch is bad you'll need to use an online vendor or buy from a scooter shop if there's one in your area.
- If the switch is good you'll need to test individual wires for continuity, refer to chapter four.Chapter Four: Using a multimeter and wire testing
- I've had many requests for an explanation on how to use a multimeter. I will go over the functions needed for the turn signal tests.
- Most multis work similar to this inexpensive one I bought at Lowes. You set the dial to the type of test you want to perform and then shuttle with the select button until you're on the specific test mode that you want:
- Here is the multi set for DC voltage testing.
- The red probe is placed on the positive source you want to test as you see in this battery test:
- The black probe is placed on the negative pole, a green ground wire, or a suitable frame ground. This bolt on the brake handle has always worked well for me for some reason. An alligator test lead can come in handy for connecting the black probe to a ground source:
- Here is a simplified diagram of the turn signal system. You can see the key is off and no power is at the black or grey wire on the flasher:
- With the key on you can see in the diagram 12v DC should be on the black and grey wires:
- To measure this as discussed in the previous chapter, the red probe should contact the black wire at the flasher connector, and the black probe be connected to a suitable ground:
- The multi probe can be carefully inserted into the connector to contact the wire for easier testing. Here you can see the black wire is showing about 12v DC with the KEY ON which is a normal test result:
- Now we test the grey wire in the same manner with the KEY ON and the flasher plugged into it's connector. It takes about 30 seconds for the voltage to stabilize once the key is turned on due to the capacitor in the flasher:
- Continuity testing with a multimeter is a very handy method for determining if a wire is good or a circuit is functional. The meter sends a small electric current between the probes and measures the resistance in ohms. If the resistance is below 60 ohms a tone will sound indicating a good wire or closed circuit, and the meter will show the ohms. You can see the continuity symbol over the middle zero that you will shuttle to with the select button. Your multi may of course vary so refer to your manual:
- If the resistance is too high indicating a bad wire or circuit, OL will show on the meter and no tone will sound. Resistance is infinite in this picture since the probes are not touching and no current can pass:
- This diagram shows how to check the continuity of the flasher ground wire. You won't get exactly zero ohms on the meter, I just put that there for illustration purposes. What happens here is the meter sends a current down the flasher ground wire, into the frame where it attaches, and back into the other probe via a ground wire or the frame:
- And here's the actual test on the multi at .2 ohms which shows the flasher ground wire is good:
- IMPORTANT! Keep in mind that bulb filaments will pass enough current to show continuity on the meter. So make sure if you use a green ground wire as a connection point for the meter that you unhook any connectors leading to a bulb so that it won't interfere with your test.
- As discussed before, the flasher has 12v DC on the grey wire. When the turn switch is activated, it connects the grey to either the blue wire for the right signals, or the orange for the left. We will check for continuity to see if the switch is making a good connection.
- Before we do so the circuits must be isolated. First, unplug the dash lights harness, as you can see the male side of the connector will be used for later testing:
- IMPORTANT: Take the rear turn signal bulbs out as the filaments will cause continuity readings from circuits we are not testing.
- Unplug the flasher for easier testing.
- We will use the turn signal wires to the front for testing. As you see in the picture, many scooters have two sets of wires for each side, one for the signal in the cowling, and the other for the mirror:
- This diagram shows how to set up for testing the left turn signal circuit. Insert a probe next to the grey wire, insert the other probe next to the orange wire at the unhooked connector, and push the turn switch to the left:
- The multi shows continuity which means the switch is good to that side:
- The same should be done for the right side which is the light blue wire, this test shows the switch is good to the right side:
- No continuity to either wire likely indicates a bad turn signal switch and it must be replaced.
- Less often it is a bad wire and you can use the continuity function to test each wire seperately to see if it is intact. As an example, here is the left front turn signal socket and orange wire being tested for continuity:
- The colored wire always goes to the center contact in the socket. If you wanted to test the ground wire you'd use the metal collar in the socket that fits around the bulb.
- This is the back of the dash on the left side pulled away from the handlebars. From the bottom to the top the connectors are: purple dot=hazard switch, green=horn button, red=turn signal switch, and yellow=high beam switch.
- If you can get into this tight spot you can test the wires from connector to connector by unplugging them. You could also test the switch directly by putting the multi probes right on the switch contacts.
- Here is a diagram that shows how the hazard switch ties in if you wish to test from it's connector:
- IMPORTANT! Wire colors will generally remain consistant throughout the scooter such as light blue for the right turn signals and orange for the left. This will help you keep track of them for testing. However, refer to your scooter's wiring diagram as a reference.
- Keeping this in mind we can now test wires from the front of the scooter to the back without removing any body panels by using the male side of the dash wire bundle.
- What I do to reach from the front to the back of the scooter with the multi is stick one end of a stripped wire into the connector slot of the wire I want to test, in this case the light blue:
- Then I clip one end of an alligator test lead to the stripped wire and the other to a probe on the multi:
- Then use the other probe to test for continuity of that wire by touching the center contact on the rear signal socket:
- Then test the left side in the same manner:
- So now you know the light blue and orange wires are good to the rear sockets. A simple test you could do now is replace the two turn signal bulbs, turn on the key, and hit the hazard switch. The two bulbs will provide enough load on the flasher to make it work:
- As an addendum to multimeter testing, you can test in many different ways if you follow the wiring diagrams. For instance, you can test to see if 12v DC is getting to the tail light contact on the brown wire by testing the center contact on the tail light socket with the key on:
- Or, turn on the key, pull in the brake handle, and test your brake light switches and wires by touching the off center contact at the tail light socket:
- These are just examples of how you can do many tests by following even generic wiring diagrams and using your multimeter.
- If you have any questions you can post them in the Clinic tech section, or click on my handle and send me a PM. Rich
..BAD TO THE BONE..
Maybe there is going to be a lot more postings on the internet regarding this. Sure hope so...
Until now...and i hope more is posted in the future. 
when i get back from my trip, i'll revisit and check out my scooter (yet again). thanks again