Fans not coming on. High speed only when jumped
08-31-2018, 12:46 AM
#1
Fans not coming on. High speed only when jumped Fans stopped coming on today.
I jumped the dark green and dark blue wires at the connector on the passenger side to ground.
High speed comes on if I jump it.
Low speed just clicks the relay.
Checked all fuses. Tried new relays.
Local tuner guy says it might be a glitch in the ECM tune because I have been uploading lots of new tunes lately.
Any other suggestions?
I jumped the dark green and dark blue wires at the connector on the passenger side to ground.
High speed comes on if I jump it.
Low speed just clicks the relay.
Checked all fuses. Tried new relays.
Local tuner guy says it might be a glitch in the ECM tune because I have been uploading lots of new tunes lately.
Any other suggestions?
08-31-2018, 07:08 AM
#2
When you ground both dark green and dark blue wires, you should get high speed fans - those are the relay coil control wires. If you ground only the dark green wire, you should get low speed fans. If so, that indicates that your relays and wiring are good with the possible exception of those two wires between where you applied ground and the PCM. It would be easy to test continuity on those two wires between the PCM and the relays. But unless something has happened that would make you suspect wire damage, I would think the PCM is not providing the necessary ground to activate the relays.
08-31-2018, 08:09 AM
#3
Fans stopped coming on today.
I jumped the dark green and dark blue wires at the connector on the passenger side to ground.
High speed comes on if I jump it.
Low speed just clicks the relay.
Checked all fuses. Tried new relays.
Local tuner guy says it might be a glitch in the ECM tune because I have been uploading lots of new tunes lately.
Any other suggestions?
I jumped the dark green and dark blue wires at the connector on the passenger side to ground.
High speed comes on if I jump it.
Low speed just clicks the relay.
Checked all fuses. Tried new relays.
Local tuner guy says it might be a glitch in the ECM tune because I have been uploading lots of new tunes lately.
Any other suggestions?
08-31-2018, 08:18 AM
#4
Overnight I let the car sit. I jumped both pins and the car turns on high speed now. Maybe I was doing it wrong last night?
This morning the fans fans were on when AC was on but shut off after a few minutes and let the car go to 265 F.
Tried jumping the wires to ground now while at work. Nothing. Fans don’t turn on. Relays click but fans don’t come on. So bad power wire somewhere?
This morning the fans fans were on when AC was on but shut off after a few minutes and let the car go to 265 F.
Tried jumping the wires to ground now while at work. Nothing. Fans don’t turn on. Relays click but fans don’t come on. So bad power wire somewhere?
Last edited by Gripenfelter; 08-31-2018 at 10:44 AM.
09-01-2018, 06:45 AM
#5
There are two fuses for the fans in the junction box under the hood. The 10 amp mini fuse is for the relay control - it should be fine since you hear the relays activate. The 40 amp maxi fuse is what actually powers the fans. It may be blown if you're getting relay action but no fans.