Dang rat chewed wire: Lost A/C and C/E light on

[bilbo99]

This is really close to a 911 because it involves the loss of A/C and I live where it hits 110* and will do so in weeks.

A couple a days ago we had a nasty rain storm and the temp dropped. I guess sometime after I got home a rat, mole, cat or chupacabra munched on a wire and did a pretty good number on it. Here is a pic:

While I have spent plenty of time inside my Exploder working on car audio, I have no idea where this wire goes and out of pure logic of cause and effect, it has something to do with my A/C compressor and it cause the Check Engine Light to come on the next morning. I still have all power to the digital A/C controls. The compressor does not come on when A/C is engaged.

Here is a pure speculative location the wire could have gone???:

Here is a shot of the whole engine bay with some markups:

On a side note, I happen to have an OBD-II scanner that hooks up to my laptop via USB. I got it as part of a carputer build in our Jetta. I tried to use the OBD-II on the Exploder and the port sends no info. Now I am very good at using it on my Jetta so its not the sensor or software. Could this wire be part of the ECU and OBD-II function? I have not checked if there is a fuse for the port. I will search on this now.

Anyone have any idea? Tried finding a wiring schematic and I guess I suc at that because I came up empty. I would love to save a minimum $300 bill at the shop on this one....

Thanks and let my know if you need other pix or info.

 

[nitro71]

Sorry to take so long to get back to you. I'd just goto the junk yard and snip off the harness you need with long wires attached and solder it on or crimp to your existing wires. Put out some mouse poison to!

 

[bilbo99]

Thanks for the reply Nitro,

I didn't get an email notification and just happened to check today and there your post was.

I get what you are saying but as I stated in the post, I have no idea where the wire goes. I only speculate that it goes to that port I circled. I already checked that by using a piece of wire with alligator clip and "completed the circuit" and it did nothing.

Now get this. The a/c compressor doesn't switch on/off when you turn the a/c on. Confirmed power to the compressor with test light. Here is where it gets VOODOO for me. When you pull fuse #10 (A/C) the compressor will kick on for 2-3 seconds when you start the engine and then it shuts off. Put the fuse back in and the compressor NEVER comes on. Tried three different fuses and checked every fuse in both Hi-current and panel.

Stuck. Cant find schematic. Can pay $27 to www.alldata.com but not sure what I'll get. Any ideas?

Thanks again. Going in the shop in a few days if I can't resolve.....hate that!!!

Sorry to take so long to get back to you. I'd just goto the junk yard and snip off the harness you need with long wires attached and solder it on or crimp to your existing wires. Put out some mouse poison to!

 

[rwenzing]

The brown connector is for the Engine Coolant Temp Sensor input to the PCM. The wire codes that should be going to it are the light green/red and gray/red that I think I see in the picture of the chewed wires up near the accessory drive. Since the PCM controls the A/C compressor, it's possible that the A/C will not work without the ECT input. I don't know that for sure - just speculating. Loss of the ECT input will definitely cause a CEL.

If fixing the ECT doesn't get the A/C working, I would look around the engine compartment for more chewed wires. In particular, take a look at the Cycling Switch near the Evaporator and the High Pressure Cut-off switch on the A/C line to the driver side of the radiator. Those switches are in series and there must be continuity through the entire circuit for the A/C to work.

The momentary actuation of the A/C compressor while starting the engine is probably CASS (Compressor Anti Slug Strategy). It is independent of normal A/C operation. The good news is that the wiring to your compressor clutch must be intact or CASS wouldn't work either.

 

[bilbo99]

Sorry for putting this really simple but it sounds like what you are telling me is to replace (splice in) the section of wire and reconnect it to the "brown-orangish connector that I have circled that has an open "port". This has me confused because its two wires and the ECT has one hole. Would they both run there? Type of connector?

We inspected completely all around the compressor and its wires and connectors are clean and solid. The whole engine and compartmant is clean. I am possitive. Oh and the compressor has power as do all the switches but something is not allowing the clutch to run more than 3 seconds.

I have had this X for little more than 2900 days (8 years) and never had a electrical problem until the day the rat ate the wire. I would be amazing odds that two that the two are unrelated. I park the car at nite, the creatures hit the wire and its to separate issues. What are the odds.

I tried an alligator wire clip with a 12" wire and probe. I put the clip on the chewed end of the wires and the other probe end into the hole of the ETC connector. I started it and switched the air on/off and it made no difference. The compressor did its 2 second spin and stopped. I must admit that it was late (twilight) when I read your post so maybe I didn't "catch" enough of the bare wired for it to work. Will get more aggressive with it. Must work on it it early am as its way to hot. Will keep plugging away. Desperately trying to save money.

Any other info is super informative. I think I have access to a schematic so I will check that out tomorrow.

Thanks for the reply!!!!

The brown connector is for the Engine Coolant Temp Sensor input to the PCM. The wire codes that should be going to it are the light green/red and gray/red that I think I see in the picture of the chewed wires up near the accessory drive. Since the PCM controls the A/C compressor, it's possible that the A/C will not work without the ECT input. I don't know that for sure - just speculating. Loss of the ECT input will definitely cause a CEL.

If fixing the ECT doesn't get the A/C working, I would look around the engine compartment for more chewed wires. In particular, take a look at the Cycling Switch near the Evaporator and the High Pressure Cut-off switch on the A/C line to the driver side of the radiator. Those switches are in series and there must be continuity through the entire circuit for the A/C to work.

The momentary actuation of the A/C compressor while starting the engine is probably CASS (Compressor Anti Slug Strategy). It is independent of normal A/C operation. The good news is that the wiring to your compressor clutch must be intact or CASS wouldn't work either.

 

[rwenzing]

Rewind... I just looked at my 5.0 Explorer engine on the stand and rechecked the schematics. I now remember that Ford labels TWO different sensors as "ECT" on our engines:

• The brown/orange connector (single red/white wire) is for the Engine Coolant Temperature sender for the dash coolant temperature gauge.
• Directly across the intake manifold to the passenger side there is a heater pipe tee with another sensor that probably has a gray connector. This is the Engine Coolant Temperature sensor (LG/RD and GY/RD wires) that provides coolant temp info for the PCM calculations.

I can't tell for sure from the pictures but it appears that the ECT sender wire may be OK. Your rat has definitely chewed the two wires off of the ECT sensor and they will need to be repaired. The first possiblilty is to use repair wire if you can access enough of the original wire for the splices near the connector. Another way is to buy the specific Motorcraft repair connector kit from your Ford dealer but they are pricey - maybe $25~30. I would also look carefully in the same general area for any more damage to wires for the injectors or other sensors.

Sorry for the confusion in the previous post.

I Googled this E-F picture of the front of an Ex 5.0 with the upper intake manifold removed. The tee with the ECT sensor is near the bottom center of the photo. The unplugged 2-wire connector appears to be laying on the lower intake manifold in the bottom right corner.

 

[bilbo99]

rwenzing you are awesome. I guess being 6'5" and not bending down to look is pretty dumb. Didn't see that gray connector back there. Just to make sure I snapped a pic a drew some crude "wires" from the chewed wires coming out of the harness to the gray connector. There is enough wire from the harness to splice into. Is there a special wire "plug" that attaches the wires into the grey connector on the ECT Sensor? I guess I can pull the connector off and look at it....when it cools down. I am hoping its just a simple splice and crimp on plug deal.

Now that I have a clue I think I can work with it.

Thanks so much!

Rewind... I just looked at my 5.0 Explorer engine on the stand and rechecked the schematics. I now remember that Ford labels TWO different sensors as "ECT" on our engines:

• The brown/orange connector (single red/white wire) is for the Engine Coolant Temperature sender for the dash coolant temperature gauge.
• Directly across the intake manifold to the passenger side there is a heater pipe tee with another sensor that probably has a gray connector. This is the Engine Coolant Temperature sensor (LG/RD and GY/RD wires) that provides coolant temp info for the PCM calculations.

I can't tell for sure from the pictures but it appears that the ECT sender wire may be OK. Your rat has definitely chewed the two wires off of the ECT sensor and they will need to be repaired. The first possiblilty is to use repair wire if you can access enough of the original wire for the splices near the connector. Another way is to buy the specific Motorcraft repair connector kit from your Ford dealer but they are pricey - maybe $25~30. I would also look carefully in the same general area for any more damage to wires for the injectors or other sensors.

Sorry for the confusion in the previous post.

I Googled this E-F picture of the front of an Ex 5.0 with the upper intake manifold removed. The tee with the ECT sensor is near the bottom center of the photo. The unplugged 2-wire connector appears to be laying on the lower intake manifold in the bottom right corner.

 

[rwenzing]

Is there a special wire "plug" that attaches the wires into the grey connector on the ECT Sensor? I guess I can pull the connector off and look at it....when it cools down. I am hoping its just a simple splice and crimp on plug deal.

Most Ford connectors can be disassembled and repaired. My gray connector has a yellow lock retainer that can be pried out easily. Under that are the electrical pins that mate with the sensor and next to each pin is a cavity with a plastic retainer clip down inside. Carefully pushing that plastic clip away from the pin with a pointed tool will allow the pin to be withdrawn from the connector.

Hopefully, you will have enough wire to solder to on the pin because finding an exact replacement pin made for this connector will be nearly impossible.

Like I said before, most Ford Motorcraft connectors are available through Ford dealers as a repair kit. The kit comes as the complete assembled connector with a few inches of wire already attached and a couple of pieces of heat shrink tubing to insulate the repair after soldering. Check with your dealer as to availability for this application.

 

[bilbo99]

I can't thank you enough. Worked on lots of older cars/trucks but stopped when they started getting complicated in the late 80's. This one seemed so obvious and simple that I knew if I could find someone with the info, who was available to give it, that I could take a shot at it.

Thanks so much. Will let you know how it goes. Thanks for the pix too!

Bilbo

Most Ford connectors can be disassembled and repaired. My gray connector has a yellow lock retainer that can be pried out easily. Under that are the electrical pins that mate with the sensor and next to each pin is a cavity with a plastic retainer clip down inside. Carefully pushing that plastic clip away from the pin with a pointed tool will allow the pin to be withdrawn from the connector.

Hopefully, you will have enough wire to solder to on the pin because finding an exact replacement pin made for this connector will be nearly impossible.

Like I said before, most Ford Motorcraft connectors are available through Ford dealers as a repair kit. The kit comes as the complete assembled connector with a few inches of wire already attached and a couple of pieces of heat shrink tubing to insulate the repair after soldering. Check with your dealer as to availability for this application.