Popping sound from speakers.

[ratty]

I have an 88 4.0 with AC and I'm having a strange issue. When the volume is up on my radio, and I switch the AC on or off or when I switch the climate control from AC to vent, there is a popping sound in my speakers. It doesn't matter if I'm on FM or AM. Happens all the time. So far I've checked the grounds and it looks fine. Was thinking it could be the HVAC or blower motor. Have been hearing some revving sound coming from under the dash when I accelerate and my AC is on too. 

[dvitha]

sounds like ground loop interference to me.

[Jeep Driver]

Run a new ground to the chassis of the radio. 

 

I'm going to suggest to you that none of your grounds are fine. If you have not been through your wiring yet, you need to. 

[cruiser54]

How do you check grounds by just looking at them?

You need to remove, scrape, clean til shiny and reattach securely.

 

I'd do this:

 

The ground point for the complete instrument cluster on your XJ or MJ is located up under the driver’s side dash. If you lay on your back and look up under there with a flashlight, without wearing a hat, you will see a black wire attached to a shiny piece of metal almost directly above the hood release knob. The screw will have either a ¼” or 5/16″ head on it.

This ground point is responsible for handling the ground circuit for the following items: Dome lamps, seat belt and key warnings, transmission power/comfort switch, wiper switch, headlamp switch and delay module, fog lamp switch, cargo lamp switch, all instrument panel grounds and illumination, power windows and door locks, cruise control dump valve, and a few more things.

The problem is that where the ground point is located does not share good contact with the chassis where the ground should be. The solution is simple:

• Make up a jumper wire with #10 gauge wire about 10″ long. On one end, crimp on a ¼” round wire terminal. On the other end, crimp on a 3/8″ round wire terminal.
•  
• Remove the screw from the existing ground wire and attach the small terminal of your jumper so that the original wire and your new jumper share the same attaching point, one over the other.
•  
• Look above the driver’s side plastic kick panel just forward of the top of the hood release knob. You will see an 8mm stud there. Attach the large terminal end there with a washer and nut over it tightened securely. Use a coating of OxGard at all ground contact surfaces when attaching the screw and nut.

**Special note for Comanche owners: Make your jumper wire 12″ long and attach it on the driver’s side kick panel close to the fusebox on the 8mm stud.**

 

[HOrnbrod]

^^^   Your OxGard link is dead.

[ratty]

3 hours ago, cruiser54 said:

How do you check grounds by just looking at them?

You need to remove, scrape, clean til shiny and reattach securely.

 

I'd do this:

 

The ground point for the complete instrument cluster on your XJ or MJ is located up under the driver’s side dash. If you lay on your back and look up under there with a flashlight, without wearing a hat, you will see a black wire attached to a shiny piece of metal almost directly above the hood release knob. The screw will have either a ¼” or 5/16″ head on it.

This ground point is responsible for handling the ground circuit for the following items: Dome lamps, seat belt and key warnings, transmission power/comfort switch, wiper switch, headlamp switch and delay module, fog lamp switch, cargo lamp switch, all instrument panel grounds and illumination, power windows and door locks, cruise control dump valve, and a few more things.

The problem is that where the ground point is located does not share good contact with the chassis where the ground should be. The solution is simple:

• Make up a jumper wire with #10 gauge wire about 10″ long. On one end, crimp on a ¼” round wire terminal. On the other end, crimp on a 3/8″ round wire terminal.
•  
• Remove the screw from the existing ground wire and attach the small terminal of your jumper so that the original wire and your new jumper share the same attaching point, one over the other.
•  
• Look above the driver’s side plastic kick panel just forward of the top of the hood release knob. You will see an 8mm stud there. Attach the large terminal end there with a washer and nut over it tightened securely. Use a coating of OxGard at all ground contact surfaces when attaching the screw and nut.

**Special note for Comanche owners: Make your jumper wire 12″ long and attach it on the driver’s side kick panel close to the fusebox on the 8mm stud.**

 

 

Thanks. I'll try this. 

[ratty]

5 hours ago, Jeep Driver said:

Run a new ground to the chassis of the radio. 

 

I'm going to suggest to you that none of your grounds are fine. If you have not been through your wiring yet, you need to. 

 

I'm slowly getting to it all. These old wires are a pain.