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sprinkles08
sprinkles08, ASE Certified Technician
Category: Jeep
Satisfied Customers: 21609
Experience:  Chrysler/Dodge/Jeep Master Certified, ASE Master and Advanced Certified, Trans and Hybrid Specialist
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ASD relay fuse keeps blowing after shifting into drive,

Customer Question

ASD relay fuse keeps blowing after shifting into drive
JA: How many miles are on the car? Has the car been starting normally?
Customer: 160k. Drove fine until today, stalled in traffic, found ASD fuse blown. Replaced fused, starts and runs fine until you shift into drive, then it blows again.
JA: What is the model/year of your Jeep?
Customer: 1996 ZJ 4.0
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Checked fuel pressure (50psi), pulled codes (no communication while fuse was blown), checked, charged and serviced battery.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No. That should do it.
Submitted: 1 month ago.
Category: Jeep
Expert:  david craig replied 1 month ago.

Hi Im David, allow me a few moments to look up some information on your vehicle. thanks

Customer: replied 1 month ago.
Ok. Thank you.
Expert:  david craig replied 1 month ago.

the wiring harness coming from the firewall can rub on it and ground to the transmission dip stick when the motor tilted while in gear! so I would take a look there first.

Customer: replied 1 month ago.
Is this the trans harness or the main engine harness? What side of the engine bay, L or R?
Expert:  david craig replied 1 month ago.

engine harness, right side if i remember correctly

Customer: replied 1 month ago.
If this harness is secure, what would be the next thing to look at? What all does the ASD Relay operate?
Expert:  david craig replied 1 month ago.

he ASD relay supplies battery voltage (12+ volts) to the fuel injectors and ignition coil(s). With certain emissions packages it also supplies 12–volts to the oxygen sensor heating elements. The Fuel Pump Relay is a separate relay controlled by the ASD relay input to the PCM. provides 12 volts to the coil side of both the relays and the ignition switch. supplies 12 volts to the output side of the relay. from the relay output to the Oxygen Sensors

Expert:  david craig replied 1 month ago.

do you still need assistance?

Expert:  sprinkles08 replied 1 month ago.

Hello and welcome to JustAnswer!

The fuse is blowing due to high current draw on the circuit or a short to ground. It's possible that the problem could be in the coil or an oxygen sensor but that would be rare, odds are the problem is a short to ground on the circuit somewhere in the harness. It leaves the ASD relay on the dark green/orange wire and goes to the oxygen sensors, fuel injectors and coil, and back to the PCM. The short could be anywhere in the harness between these components. If it only happens in drive most likely it's because of the slight powertrain shift when the trans is put into gear and its allowing the damaged area to short to ground.

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