Thread: My Ecu Relay Is Buzzing Like Crazy HELP !

Happening On A 93 Sentra Se-R .

I Recently Put A New Harness On & Now Having An Issue . The Relay To The ECU (Green Relay) Starts Buzzing . Once I Disconnected It Everything Started Working . Before I Wasnt Getting Fuel & When I Took The Relay Off I Got Power To The Pump . Would That Mean My Relay Is Bad Or Is Something Else Messed Up .

Went The Next Day To Try To Figure Why Im Having This Issue . I Left The Ecu Relay Off & Noticed As I Turned The Key To The On Position The Fuel Pump Relay Starts Buzzing .

I Didnt Touch Anything On The Harness . Just Swapped Out The Old Harness & Replaced It With This One . All The Plugs Are Connected & All The Grounds Are GROUNDED . Fuses Are All New .

Not Sure Whats Going On Or What The Problem Is .



Update .

I Double Checked All The Plugs And Wires . All Seem Fine And Everything Matches . Now As I Turn The Key The ECU Green Relay Still Buzzes But Now I Have The Bottom Blue Relay By The Under Dash Fuse Box Buzzing Also

Update 10-23-2012

So Today I Look At All The Plugs To Make Sure All The Wires Are Matching At The Connectors . Everything Is Good All Wires Are Matching . Also The ECU Light Is Working Again So I Now Kno That The ECU Is Working . But The ECU Relay Still Continues To Buzz And I Also Notice That The Square Black Relay Above The Main Harness Box (Main White Connector) Is Humming . What Can Cause That To Go Off .

i also tried to replace the relays and nothing still the same issues .

You double checked that there wasn't any crossed / broken wires?

You didnt plug the coil wire into the reverse switch and vise versa?

Make sure your connectors are all in the right spot. The coil wire is the one with the black w/red stripe and thicker wires and on the same section of the harness as the ignitor, make sure you also didnt cross the ignitor plug with the o2 sensor plug. Ignitor plug has the green w/ yellow stripe, white signal wire and black wire for ground.

i did a complete harnest swap once on a 93 rhd and i had the same problem. i found the problem behind the dash around the radio and blower switch area. there 2 connectors that could plug and lit like perfect but its incorrect. just switch the connector and see if ur problem solve. it solves mine

yeah that could be it too, double check where you connected your smaller 3 wire connector into being that supplies the 12v ignition positive to the relay and to the ecu and also the fuel pump trigger ground going to the ecu

ok thanks i will look over the wires / plugs and see if i misplugged something .

Update .

i double checked all the plugs and wires . all seem fine and everything matches . now as i turn the key the ECU Green Relay still buzzes but now i have the bottom Blue Relay by the under dash fuse box buzzing also

i also checked all the grounds . i relay dont know what else to do .

why did you replace the harness to begin with?

There are a couple plugs that can be reversed, the coil, the interior plug that supplies the ignition and constant powers, the knock sensor and aux air control valve under the intake manifold and the ignitor chip and o2 sensor plugs.

Check all of those. Again if you wernt having this issue before the harness swap and now are, its an obvious mis plug of something.