Uploaded December 2020 | Updated September 2026, 2 weeks ago
[Tools/Parts]
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How to Properly Test a Car Relay - Relays 101 - Resistence Check
The car in the video is a Mustang GT 2003 V8 4.6L. However, the procedures shown in the video will apply to most vehicles and applications.
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#Relays #CarRelays #Relay
A relay is an electrically operated switch. Think of it as a remote switch which is turned on by an electrical circuit and not a human.
A starter motor will draw as much as 250 amps when starting an engine. In order to handle that sort of current draw you require large gauge wires to avoid overheating and damage to the wire insulation, etc.
A starter relay acts as an electrical circuit completer or circuit breaker in between the vehicle's battery and the starter motor.
The relay (actually a solenoid, but it serves the same purpose) in the starter circuit allows you to switch the high-current power to the starter motor on and off using low-current control circuitry.
Without it, all the control circuitry would have to be able to withstand the high current drawn by the motor. This means much larger, heavier, and more expensive parts have to be used. It also means there are more locations where potentially dangerous high currents would be present, increasing the risk of a small failure becoming catastrophic.
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Connect the car battery to 85 and 86 on the relay. You will hear a click. Every mechanical relay has a little electromagnet in it, and when it is energized it pulls the internal switch contacts together. That makes an audible clicking sound. You also can feel the contacts closing if you lay your hands on the relay. The internal electromagnet that opens and closes a circuit to stop and start the flow of electricity
Typically...
pin 85 is ground (negative)
pin 86 is power (positive)
pin 30 is constant supply power to whatever is being activated by the relay
pin 87 is the output of pin 30 when it gets switched on. 30 to 87
To be certain which pin (85 or 86) is positive or negative...the diagrams often have a symbol of a diode (triangle and a line) on either pin 85 or 86, whichever pin the "line" side of the diode symbol goes to is negative.
Connecting power backwards will simply do nothing, this is what the diode does.
Video Title: How to Properly Test a Car Relay - Relays 101 - Resistence Check
Video File Created Date: Sunday, 29 November, 2020 (Video may or may not have been captured on this date, it shows the date the video was last converted.)
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Video Tags:
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[Tools/Parts]
Cheap Multimeter: amzn.to/3raflQg
Crocodile Clip Cables: amzn.to/2Wtoohl
How to Properly Test a Car Relay - Relays 101 - Resistence Check
The car in the video is a Mustang GT 2003 V8 4.6L. However, the procedures shown in the video will apply to most vehicles and applications.
WATCH THE OTHER VIDEOS ON MY CHANNEL!!! I REPLACE: TIE RODS, LOWER BALL JOINTS, CV AXLES, SWAY BAR LINKS AND MORE!!!
SUBSCRIBE FOR MORE!
#Relays #CarRelays #Relay
A relay is an electrically operated switch. Think of it as a remote switch which is turned on by an electrical circuit and not a human.
A starter motor will draw as much as 250 amps when starting an engine. In order to handle that sort of current draw you require large gauge wires to avoid overheating and damage to the wire insulation, etc.
A starter relay acts as an electrical circuit completer or circuit breaker in between the vehicle's battery and the starter motor.
The relay (actually a solenoid, but it serves the same purpose) in the starter circuit allows you to switch the high-current power to the starter motor on and off using low-current control circuitry.
Without it, all the control circuitry would have to be able to withstand the high current drawn by the motor. This means much larger, heavier, and more expensive parts have to be used. It also means there are more locations where potentially dangerous high currents would be present, increasing the risk of a small failure becoming catastrophic.
-----
Connect the car battery to 85 and 86 on the relay. You will hear a click. Every mechanical relay has a little electromagnet in it, and when it is energized it pulls the internal switch contacts together. That makes an audible clicking sound. You also can feel the contacts closing if you lay your hands on the relay. The internal electromagnet that opens and closes a circuit to stop and start the flow of electricity
Typically...
pin 85 is ground (negative)
pin 86 is power (positive)
pin 30 is constant supply power to whatever is being activated by the relay
pin 87 is the output of pin 30 when it gets switched on. 30 to 87
To be certain which pin (85 or 86) is positive or negative...the diagrams often have a symbol of a diode (triangle and a line) on either pin 85 or 86, whichever pin the "line" side of the diode symbol goes to is negative.
Connecting power backwards will simply do nothing, this is what the diode does.
Video Title: How to Properly Test a Car Relay - Relays 101 - Resistence Check
Video File Created Date: Sunday, 29 November, 2020 (Video may or may not have been captured on this date, it shows the date the video was last converted.)
-- Video uploaded and managed using YouTube Bulk Uploader for the Lazy!
-- Manage and Auto-Tag your YouTube videos offline... Then upload!
-- ginkosolutions.com/youtube-bulk-uploader
-- GinkoSolutions.com
Video Tags:
how to, test, car, relay, relays, resistence, check, car relay, car relay testing, how to test a relay, testing a relay for resistence, resistence check, resistence test, relay resistence test, relay resistence check, relays 101, car relays 101, properly test a car relay, car relays explained, car relay problems, car relay attack, car relay tester, car relay box, car relays and fuses, relays explained, relays how they work, relays in cars, relays and switches
