Have a 4.6L? Here's a problem I bet you all have...

[Ryno5236]

Thank you

Wow ive been trying to figure out this a/c thing for a few thanks hope thats my prob.

 

[palin3]

Hi KC10Chief,

Thanks for the info, I was not able to repair myself but went to a small repair shop where they could put it on a lift and they found the problem. Broken wire, wouldn't of found it if it wasn't for your post.
I had 2 Ford dealers tell me the only thing it could be was to replace the computer module, at a cost of $1500 plus labor for reprogramming the module.

Instead the cost was a couple of hundred dollars for them to fix the problem.

Once again Thank You very much.
palin3

 

[Pontisteve]

A couple hundred bucks for them to fix a few wires, when you pointed out to them exactly what and where the problem was?? That was not a good deal my friend.

Somewhere in the $125 and under range is more like it. An hours labor at whatever rate your shop charges.

It's finding the problem that's often costly, and that is not the case here.

 

[ATLDON]

I would like to thank to creator of this thread. My 2003 Mercury Mountaineer wouldn't start while I was at the local mall and had to tow the vehicle home. I replaced the starter relay, then the starter yesterday and still it would not start. I found this thread and looked under the vehicle and found a big gash in the harness. After about an hour of time and A LOT of effort I got the harness out and the small starter wire was cut....only a few strands intact. So I bought 5 ft of 12 gauge wire, spliced the cut and reinstalled the harness. The vehicle started immediately.....

 

[Pontisteve]

So do we know exactly which wires are in this harness? It appears to be the following:

Large positive battery cable (battery to starter)
AC Clutch wire (relay box to compressor??)
Starter signal wire (relay box to starter??)

Any others, or fill in the blanks?

 

[elwood01]

Thanks KC10Chief!

You must be a KC-10 Crew Chief? I was a Crew Chief on C-141B's! Anyways, enough airplane talk. Great post! & very helpful! I just did the repair today on a 2003 Explorer 4X4 4.6L, it was straight forward, without too many difficulties. The hardest part was getting the plastic stand-off clip detached from the post, near where the small wire goes up to the A/C compressor & the bundle makes a bend aft. towards the starter. Once I had the bundle out of the L/H wheelwell, & cleaned it up, the only damage was an almost severed A/C wire. After repairing the wire with a butt-slpice & some heat-shrink. I also used a 4in. piece of 3/4in. heater hose with ty-raps to help protect the bundle in the area of the damged wire. I also took a small corner off the plastic scupper of the oil filter & bent the metal wire bundle bracket up just a little, to insure I had good clearance, & no more rubbing! Quick, cheap, & long-lasting repair!

 

[Pontisteve]

Fixed 03 Explorer 4.6 wiring

So today, I decided to tackle the job on my 03 Explorer 4WD 4.6 as well. Along the way, I decided to document the fix since this is apparently a very common issue.

Here's the damage...

Here's the damage when the harness is unwrapped and wiring exposed...

Here's the harness sticking out the drivers fenderwell...

Here's a step by step on how to fix it.

1) Disconnect battery - 8mm wrench
2) Pull one clip out of the flexible fender liner material in the RF wheel well, to expose the side of the AC compressor.
3) Unplug AC Compressor clutch harness connector.
To do this, squeeze the tab on the clip and pull the connector off. This was the hardest part of the job, due to the awkward location of the connector. I was on my back, with one hand thru the fender liner and the other hand up the front of the motor. My legs were under the truck facing rearward, and my right elbow was just above the power steering cooler. Watch the cooler, it's sharp.
4) Unplug the oil pressure sending unit harness connector. Squeeze the tab on that clip to remove also.
5) Remove LF wheel and support the truck with a jack stand.
6) Remove both starter wiring nuts, 13mm and 10mm sockets, 1/4" ratchet.
7) Unbend the harness holder that's right behind the AC compressor, to get the harness out of it. You'll need some sort of tool, because it's pretty strong. I used a door panel clip removal tool. It's basically a screwdriver body with a V shaped chrome end on it.
8) Unbend the harness holder near the oil filter. I found it easier to both unbend it and unbolt it from the front of the motor, two 10mm nuts.
9) Remove the harness holder from the harness and set aside.
10) Pull the harness up thru the left inner fender liner. Note the routing of the harness first!
11) Remove the harness wrap about 6" in both directions from where the damage is. That should be right about where the oil pressure sensor connector harness branches off.
12) Repair the harness.

In my case, the harness had a hole in it, and oil had worked its way into the harness further than you might think. So I opted to remove all the wiring harness wrap from the entire harness that I could get to, clean everything up with brakleen and paper towels, and rewrap everything with fresh electrical tape. I also rewrapped the ends of the harness with cloth tape, just like the factory did.

I also opted to remove a couple inches of bad wiring, and solder in a short replacement section. I made sure to use soldering flux to clean the original wiring before soldering, as it looked dingy. I also heat shrinked the wiring. Don't forget to slide the heat shrink on before doing the soldering! If you use a butt connector, get the good ones that are waterproof and have heat shrink built in. Crimp, heat up the shrink, and done.

13) Reinstall as removed. Be sure to get the routing right before plugging anything back in.
14) Bend the harness brackets with a pair of duckbill pliers, so that the harness is held in a natural position, not kinked. Keep the harness away from everything. I found that the harness was also vulnerable to sitting right on top of some power steering lines, which could rub a hole in the harness over time. So follow the entire harness with a flashlight and make sure you have a fingers width between the harness and everything else at all times.
15) Remove the oil drain slide (three 13mm bolts), and trim some off. Be sure not to trim too much off. You'll have already gaines some clearance by getting the wiring laid out and the brackets bent to a better shape. But I trimmed also, to make sure. Make sure you don't trim so much that the oil drips off the filter housing and onto the ground instead of the slide.

That's it. The hard parts were removing the harness connector on the AC compressor, cleaning the oil that had worked its way into my harness wrap, and getting the harness to feed in and out of the LF fenderwell. That took a couple back and forth trips from the side of the car to under the car. Two people here would have been nice. Putting the connector back on the AC compressor proved hard as well. Push hard until it clicks.

In my case, there were 2 damages done. The white wire w/ red stripe was completely broke in half, and the positive battery cable was cut into, but not much. Since the cable was still mostly there and good, I opted to get out my big heat shrink tubing, unwrap the entire harness, and heat shrink over the damaged battery cable. If the damage was worse, I would have had to replace the + battery cable.

I also took the time to note the wiring and see what all was in there...

Large red cable - positive battery cable to starter
Yellow/blue wire - Starter solenoid
Gray/white wire - AC Compressor +
Black wire - AC Compressor -
White/red wire - Oil Pressure Sending Unit

So in my truck the oil pressure sending unit wire was cut in half. The positive battery cable was cut into, but not badly damaged. However, the two exposed wires could have touched each other, sending 12v into the oil pressure sending unit wire. Who knows what evil that could cause.

Here's the fixed wiring...

And finally all buttoned up...

 

[zecolleman]

Thanks a lot got my a/c back

 

[007]

Yep, found this issue on our '04 XLT Sport summer before last when changing the oil. I saw that the split loom and starter battery wire insulation was missing in a 1/4" circle behind the oil filter drip shield. I covered the mess up and let it alone until the A/C stopped working over the course of 3 hours last summer. The truck went to the dealer for a regular tranny flush/fuel filter and mentioned the A/C issue. The service writer actually mentioned the harness issue when I mentioned the abrupt failure. I had them look at it and the whole harness was repaired at the dealer for about $100 since it was already there.

I found it refreshing the service writer and tech knew about the problem and weren't doing the typical BS about throwing out several random high-dollar guesses.

 

[Pontisteve]

On a side note, I had another AC issue on a recent trip. Every time the motor was under a heavy load, the AC would quit blowing out the vents and start blowing out the windshield defroster.

Saavy car guys know that the floor/windshield position is generally the default position, and that there is an engine vacuum line that goes from the engine to the AC control unit. From there, the control unit passes this vacuum on to various actuators to cause the AC flap doors to open or close accordingly.

Knowing this, I realized that at heavier throttle positions, my engine has less vacuum, and the AC control unit was unable to provide enough vacuum to the correct actuators to keep the correct doors open. A quick look under the hood on the passenger side of my 4.6 V8 engine revealed the problem. A vacuum line going from the AC control unit to the heater control valve had come unplugged. This caused a general loss of vacuum to the system, weakening the signal to the AC flap doors. Under heavy engine load (going uphill for example), the weakened vacuum signal was unable to keep the actuators vacuum-filled.

I don't know if this is a common issue or not. The fix was simple. Plug it back in. The heater control valve is on the passenger side of the engine near the valve cover. It's black plastic, and has heater hoses going in and out of it. The vacuum line plugs into the back side (towards rear of vehicle) of the heater control valve. Plugging it back in fixed it right up.

 

[FordLover]

I just fixed this on my very late build '02 with 55K miles. Since none of my wires were damaged yet, I simply used a thick metal rod (about the size of a pencil) and ziptied it to the bottom of the harness. That metal rod will do a ton of damage to the plastic funnel long before the plastic funnel will do damage to the piece of steel..

 

[red82gt]

05 Limited, 130,000KM. Full on copper showing.
I had my wife take it into the dealer while I was out of town working for a few weeks, they charged $250 and couldn't find the problem.

Thanks for posting this thread, I would have turned the whole wiring harness inside out looking for for that short in the system!

 

[fourortwowheels]

i joined this forum just to thank you for this thread! thanks to that dumb piece of plastic and a simple little wire, i just inherited a 2003 Mountaineer Premier w/ 65k on it for nothing LOL. i mean talk about a dream scenario.... the last 2 mechanics told my poor aunt that they couldnt find the problem, its probably going to cost $1000 for a new gauge cluster, etc. so she basically wrote the car off and got something new while this truck sat for 1.5 years. low and behold, i do a google search for no oil pressure dummy light and this magical thread pops up.

got under the car 2night, found the problem and fixed it! now wifey has a new truck for $tax/title/transfer plates woooot! the interwebz worked for me tonight, thank you ford nuts!

 

[EdPrymak]

2002 Ford Explorer xlt (i think )

Its my girlfriends car and i think that it is an XLT or something like that...2002...v6...2wd...
anyways....for 2 days now i have been on here and some of the info most definitely helped and i have learned alot...just now ran out of day light and i would like to have somewhat of a plan for tomorrow ...anyway..here is what happened..
she drove the car home..shut it off and now it wont start..thought it was the battery but it is not i had it tested and (being brand new) it is good 100%
then i saw a post here somewhere about a fuse that maybe blown and one of the fuses was blown ...it was the #9 fuse in the power distribution box which is power point #1? not sure what that means...
the car clicks repeatedly when i turn the key the whole way...should i go ahead and get a new starter? or just the solenoid? when i crawled underneath the car and told my girlfriend to crank it i put my hand on the started and it keeps clicking inside..not sure if thats normal or what... i also did replace the battery connections...so that should be all good....
when the car is cranked...the gages go nuts though...not the normal "gages on" type of behavior...any suggestions about what i should do tomorrow?>
thank you so much!

 

[Pontisteve]

Clicking like that and the gauges going nuts is a sure sign your starter is not getting adequate power. Normally it is a dead battery, but it could be a wiring problem between the battery and starter. Technically, you should test voltage at the starter while cranking.

This thread may also describe your problem. The small start signal wire and the positive battery cable are both potentially affected by the issue this thread describes.

Its not your starter or solenoid. Dont waste your money. Its the battery or wiring to the starter. Check battery voltage while cranking. Should remain above 11.5 volts. If ok, check voltage at starter. Small wire should get battery voltage while cranking. Large cable should have battery voltage all the time.

Could be a corroded positive or negative cable. Could just be the battery terminals are corroded.

Most likely issue is bad battery or crap battery terminals. Next likely would be the battery cables.

 

[SyberTiger]

I checked my wiring harness this morning. Although I've changed my oil myself 40 times in this vehicle and have seen and cleaned this wiring hardness many time I've never seen damage to it. Clearly, the damaged side is the side you would not be able to see from the bottom of the vehicle. However, using my hands I felt around and sure enough could feel where the plastic oil drip director was rubbing on the cable's protection sheath. It didn't feel like it rubbed all the way through. I took a piece of 1/2" ID rubber hose and split it and put it over the area where it rubs. I used a plastic tie-wrap around the rubber hose to keep it in place. Now there's a rubber buffer between the plastic oil drip director and the cable sheath. Kudos for the writeup. You probably saved me a big headache down the road I'm sure.

 

[Traillover]

WOW, do I love this blog.... After reading your posting, I checked my 03 and yap, there it was... Worn all the way through the plastic but not the wiring! THANK YOU VERY MUCH!

I laughed after reading a few reply's to you because my first impression after reading yours was wrap it with some rubber hose and secure it with Gorilla Tape... So, did that and bent the metal holder down and away from the plastic shield....

 

[gsmaclean]

I've been watching mine ever since I first saw this topic. This weekend I checked mine again while changing the oil, and discovered that the plastic loom had been worn through - no damage to wires though.

I pulled the plastic funnel piece out, and cut a piece away so that it's nowhere near the loom anymore. Put it back in, problem solved (or averted).

Thanks!

 

[FordFool2]

This informative post made me look. Mine was in perfect condition. I did notice there is a factory installed brace securing the loom near the oil filter drain director. It is mounter to the front corner of the engine and about 5-6 inches in length. It wraps around the loom as an anchor point to suspend the loom just below the plastic drain and above the crossmember. Mine is an '04 EB 4x4 4.6L. Maybe the 4x4s got this extra brace/bracket?

 

[Pontisteve]

This informative post made me look. Mine was in perfect condition. I did notice there is a factory installed brace securing the loom near the oil filter drain director. It is mounter to the front corner of the engine and about 5-6 inches in length. It wraps around the loom as an anchor point to suspend the loom just below the plastic drain and above the crossmember. Mine is an '04 EB 4x4 4.6L. Maybe the 4x4s got this extra brace/bracket?

They all have the rubber-coated metal wire holding bracket that goes to one of the front bolts on the timing cover. My 4wd does. I think the problem might be how they routed the harness at the factory. Some trucks may have had the wiring end up below the oil drain, and some above it. I think if it's above it, the rubbing begins.