Q: Relay for engine management doesn't work unless the magnetized plate is pushed in. Please help!

asked by on

I tried to jump power from fan fuse to engine management fuse and it sparked then wouldn't start.. found that pushing magnetized plate in it would. Start ... put in a good working relay and it still needed to b pressed for constant power.... what would cause a relay to not work unless engaged manually... Please help i am in need of assistance ....

My car has 200000 miles.
My car has an automatic transmission.

Generally speaking, there are two separate circuits inside of a relay. One circuit is, what I’ll refer to for the sake of this writing, as the "supply" side, and the other is the "signal" side. The supply side has a positive and negative post, and is what supplies voltage to the component being controlled, by way of the switch inside the relay. The signal side also has a positive and negative, but the signal side is what actually commands the switch inside the relay to close, and allow voltage to flow through the supply side. This is the reason there is typically four posts on a relay.

If you have to manually push the switch closed to get the circuit to work, then something is keeping the supply side from getting the signal necessary to close, and allow voltage to flow through the supply side. Without knowing the model of the vehicle, I’m not sure if the computer controls the voltage, or the ground, to complete the circuit.

You would need to get a wiring diagram and test the individual pins in the fuse box to see if there is a voltage or ground signal that isn’t being supplied when commanded. Once you figure out what signal is being received, then you have to figure out why. These situations are where a certified mechanic becomes valuable. If you would like to have this taken care of, a certified professional from YourMechanic can come to your car’s location to inspect the electrical system and proceed with the proper repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Relay for engine management doesn't work unless the magnetized plate is pushed in. Please help!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: overheating problem

Thanks for writing in about your Hummer H2. Let's cover the basics of diagnosing a overheating issue. First, verify the actual temperature at the thermostat housing. Cooling system (and cap) has probably been pressure tested by now. If it tends...

Q: Parasitic drain 2005 tahoe on ignition a fuse

Hello, thank you for writing in. Great job on the electrical testing thus far! A wiring diagram for the vehicle will work wonders for you if you can obtain one. If you are referring to the ignition switch fuse, then...

Q: Gear shift cable broken

Hello, depending on how the shifter cable is broken, the cable, the linkage, or both might have to be replaced. The only way to see what has failed is to visually inspect the cable and linkage. You may have to...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...