How to Install a Starter Relayby Marion Cobretti
The starter relay on your vehicle acts as the middleman between the ignition switch and the starter motor. When you turn the ignition key, a small current is sent to the relay that causes the relay to close the circuit within it to provide power to the starter. If the starter relay fails, you won’t be able to start the engine. Damage to the starter relay often happens from a bad power connection on the starter that causes it to short circuit. A nonworking relay cannot be dismantled for repair; you will have to install a new one in order to start the engine. You can replace the starter relay right at home; with a few tools, it should take 10 minutes to do.
Raise the hood on your vehicle and then locate the battery.
Use a socket wrench to remove the black wire from the battery. It will be identified with a minus (-) symbol next to its post.
Wrap electrical tape around the metal terminal at the end of the cable until no metal is visible and then lay the cable down on the side of the battery case.
Locate the Power Distribution Center (PDC) within the engine compartment. The PDC contains your vehicle’s major fuses and relays. It normally mounts on the right, or driver’s side, of the engine compartment and has a square black plastic cover over its relays and fuses. If you have trouble locating it, check your owner’s manual under “FUSES” or “RELAYS.”
Check the top of the PDC cover for relay and fuse mounting locations. Some vehicles have this information on the top of the cover and some have the information on the inside of the cover once you remove it. If you don’t see anything on the top of the PDC cover, remove it by pushing in the plastic tabs on the sides of the cover and then lifting the cover straight off.
Read the information on the PDC cover. The fuses will look like rectangles and have individual names next to them, according to what they power. The relays will be shaped like squares and have names in the center of each square to let you know what they power as well.
Locate the relay square on the PDC cover that says “Starter Relay” at its center. Identify the corresponding relay mounted in the PDC.
Remove the starter relay by placing a pair of relay-puller pliers around the housing of the relay and then pulling the starter relay straight out vertically. Do not twist or turn the relay because it is not screwed in.
Install the new starter relay by hand. Match up the metal or copper blades at the bottom of the relay with their correct slot in the PDC. Then place the new starter relay in position and gently push down on it until it seats itself completely back into the PDC.
Reinstall the cover for the power distribution center and then remove the tape from the battery cable’s terminal.
Connect the cable back to the battery and tighten its bolt until snug. Set your 3/8-inch drive torque wrench to 12 ft-lbs. and then completely secure the battery cable in place.
Start the engine to check the repair.
- "Haynes Automotive Electrical Manual"; John Haynes; 1990
- "Alternators and Starter Motors"; Robert Bosch; 2003
- If your vehicle does not start after changing the starter relay, check all of the wires going to the starter. Some of the wires may be rusted or have a lot of corrosion on them. If that is the case, clean the wires using a small wire brush. If any of the wires have cracks in the sheathing, chances are the entire wire contains corrosion. Replace any wires that have damaged sheathing.
Things You'll Need
- Socket wrench set
- Electrical tape
- Vehicle owner’s manual
- Relay puller pliers
- 3/8-inch drive torque wrench
Marion Cobretti began working as a freelance writer in 2006. His work appears on Newsvine and other websites. Cobretti completed a three-year course in automotive technology and is currently seeking an Associate of Applied Science at Macomb Community College.