GMC 11516051 Flasher,Hazard Lamp & Turn Signal Lamp

On models equipped with a Delco Loe II anti-theft audio system, be sure the The lockout feature is turned off before performing any procedure which requires disconnecting the battery. When the flasher unit is functioning properly, an audible click can be heard during its operation. If the turn signals fail on one side or the other and the flasher unit does not make its characteristic clicking sound, a faulty turn signal bulb is indicated. If both turn signals fail to blink, the problem may be due to a blown fuse, a faulty flasher unit, a broken switch or a loose or open connection. If a quick check of the fuse box indicates that the turn signal fuse has blown, check the wiring for a short time before installing a new fuse. To replace the flasher, simply pull it out of its electrical connector. Make sure that the replacement-unit is identical to the original. Compare the old one to the new one before installing it. Installation is the reverse of removal. The hazard flasher is checked in a fashion similar to the turn signal flasher. To replace it with another one, simply pull it out from its connector under dash and install a new one instead. Make sure you compare this one with another one before fixing into position in order to ensure you don't fix an inferior unit as you dispose off an authentic brand replacement part which would have taken long trouble and time "to find." Installation is done by reversing what was done when removing it.

First, several electrical accessories in the vehicle use relays to transmit the electrical signal to the component and if the relay is defective, that component will not operate properly. The various relays are grouped together in several locations like the engine compartment. If a faulty relay is suspected, it can be removed and tested.

Note that 2008 and later models do not use a turn signal relay, as the Body Control Module (BCM) controls the turn signal function by pulsing the voltage to the right or left turn signal lights after sensing the position of the turn signal multi-function switch. Begin by removing the left side knee bolster. Next, take out the relay center mounting bolts, which are located underneath the steering column; to access this area, first remove the knee bolster and then take out two bolts to carefully lower the relay center. After lowering the relay center, remove the turn signal and hazard flasher relay from the relay center. Finally, installation is the reverse of removal.

Quite a number of electrical accessories in the vehicle use relays to pass current to the component, and if the relay is faulty, then the specified component will not function as expected. That fuse is more often found in the engine compartment fuse and relay box, while some are found in the several wiring harnesses underneath the instrument panel. The suspected faulty relay can be readily withdrawn and checked using a certain procedure or may be referred to a dealer service department or a competent repair shop and since the relays come as assemblies or assemblies of required relays that have become faulty, they must be replaced as a whole. Many of the relays utilized in these automobiles are termed as "ISO" relays and bear numerical suffixes referring to their typical circuit connections/uses; the ISO relays essentially have two classic types of terminal arrangements. In order to find out which wires are connected in which manner, the wiring diagram for the circuit in question must be consulted, and in the absence of this information the following facts may be helpful. The two terminals on the right are for the relay control circuit and connected to the relay coil while the other two are of the power circuit. In the energised state of the coil, the larger contacts of the power circuit are closed to allow energy to flow to the circuit loads. The control circuit is usually terminals 85 and 86; if the diode is present the 86 must go to battery positive and 85 to ground if the resistor is present either end of terminal 85 or 86 can be connected. Terminal 30 is used to link the unit to the battery voltage to the circuit loads while terminal 87 connects to the ground side of circuits. Continuity checks can be done on relay control coil using an ohmmeter by placing leads on the meter in correct polarity then switch the sides of lead to check for continuity in the other direction. If a resistor is present, the resistance should be equal whether in forward or reverse polarity, if a diode is present then resistance should be higher in forward polarity. Thus if there is an infinite resistance in normal as well as in the auxiliary circuit, it call for replacement of the relay. Once the relay is removed continuity should be tested between the power circuit terminals, there should be no continuity from terminal 30 to 87 when the circuit is de-energized. If a fused jumper wire is connected to terminal 86 and the positive battery terminal and another end of the relay to pin 85 to ground the relay should click. When the jumper wires are connected, there should be continuity between terminal number 30 and 87. Where any of the above tests fail, the relay should be replaced.

If both turn signals fail to blink, it may be due to a blown fuse, a faulty flasher unit, a broken switch, or a loose or open connection.

Remove the bolt that secures the large bulkhead electrical connector to the firewall.

The wiring should be checked for a short circuit.

Separate the two multi-function switch connectors from the large bulkhead connector.

If a faulty relay is suspected, it can be removed and tested by a dealer service department or a repair shop.

To replace the hazard flasher, the under-dash panel or knee bolster needs to be removed for access and the flasher needs to be unplugged. The replacement unit should be identical to the one it replaces.