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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Transmissions
Satisfied Customers: 6215
Experience:  ASE Master Certified. ASE Gasoline Engine Performance Certified,Ford Senior Master Technician
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Starter tries to engage when in reverse. I thought problem

Customer Question

Starter tries to engage when in reverse. I thought problem was digital transmission range sensor - replaced it, problem still occurs.
JA: Which particular sensor are you asking about? And have any trouble codes been triggered?
Customer: No trouble codes
JA: What is the model/year of your Ford?
Customer: 2003 expedition. 5.4 engine
JA: Are you fixing your Expedition yourself? What have you tried so far?
Customer: yes replaced DTR sensor. Also took out started solenoid fuse to see what happens in reverse - reverse lights turn on as appropriate; however as mentioned starter engages.
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 2 months ago.
Category: Transmissions
Expert:  A. Penland replied 2 months ago.

Do you have any other electrical problems like the wipers, power windows or dome light issues?

Customer: replied 2 months ago.
No other electrical issues
Customer: replied 2 months ago.
I am getting the feeling that the problem I am having is unrelated to the DTR sensor.
Expert:  A. Penland replied 2 months ago.

Yes it is. Try this please. Remove the starter fuse in the dash fuse box, #101 which should be a 30 amp fuse and see if it still engages the starter in reverse.

Customer: replied 2 months ago.
Took out fuse 101. Does not try to start.
Customer: replied 2 months ago.
Of note - the problem where it tries to start in reverse has been intermittent. It is more common now, but still intermittent at times
Expert:  A. Penland replied 2 months ago.

I understand. Does it do it worse when it is raining or when the vehicle sits for a while ?

Customer: replied 2 months ago.
No difference that I can tell
Customer: replied 2 months ago.
After I replaced the DTR sensor this evening it was doing it about all the time. I switched back and forth with the old/new part and kept having the problem. I inspected the wiring harness - everything looks pretty good
Customer: replied 2 months ago.
I also took out fuse 101 earlier to make sure the backup lights came on when in reverse - it did, and I was able to crank in N and P, so I felt good about the alignment.
Customer: replied 2 months ago.
I was able to crank with the fuse in, BTW
Expert:  A. Penland replied 2 months ago.

Check the dash fuse box for any water, green corrosion or signs of water in the electrical connectors or water staining on the fuse box. We have seen water leaking in around the cowl panel and causing electrical problems with the dash fuse box. The back up light circuit goes from the range sensor to the fuse box and then out to the back up lights. Also, since you can start the engine with fuse 101 removed proves there is a problem with the fuse box.

Customer: replied 2 months ago.
I cannot start the engine with fuse 101 removed. The fuse box looks real clean - I'll inspect closely
Customer: replied 2 months ago.
The wires that run back from the range sensor to the fuse panel - are connections made behind the fuse box? Do I have to get behind it to see if there are any problems. The starter circuit obviously runs through the fuse panel as does the reverse circuit - maybe something is happening inside/behind the fuse box?
Customer: replied 2 months ago.
Fuse book looks good - no signs of corrosion
Customer: replied 2 months ago.
Fuse box (not book)
Expert:  A. Penland replied 2 months ago.

Slow down and give me time to respond. Every time you reply, I have to retype my reply.

Take out fuse #14 and see if the problem is still present.

Customer: replied 2 months ago.
Sorry about replying too quickly. Of course the problem is not presenting itself now, so I cannot tell if taking out fuse 14 helps. All I can do is try that when the problem comes back (which won't be too long). I'm going to drive it for a while (instead of the wife) so I can try this as soon as the problem appears.
Expert:  A. Penland replied 2 months ago.

No problem. It takes me a little time to get my respond gathered together properly.

Fuse 14 is for the back up lights. Also, I can walk you through a couple of electrical tests to verify the cause of the problem. I really do not like guessing, it cost way too much.

You will need a digital multi meter or a test light.

Customer: replied 2 months ago.
I have a digital meter. I'm running out of time for this evening, but we can try a few things. Would it be better/quicker to pull fuse 14 when the problem reappears?
Expert:  A. Penland replied 2 months ago.

Yes, when it is frequent.

It is getting late here also and I have big storms rolling into my area. I'm in Florida, go figure.

We can continue tomorrow. I will be back on line after I get off of work from my dealership.

Customer: replied 2 months ago.
Sounds good. Chat soon. Thanks
Expert:  A. Penland replied 2 months ago.

Your welcome. Talk to you tomorrow.

Customer: replied 2 months ago.
Did a few things
1. After coming home from work (20 mile drive), the problem presented itself. With the engine on or off, when moving between P R and N, the starter would intermittently engage when moving into R from either P or N.
2. Pulled fuse 14 and the problem did not present itself.
3. Let the car sit for ~90 minutes
4. The problem would not present itself.
5. Drove around for 5 minutes or so and the problem presented itself again. There may be a component to this problem where the car has to be warm.
I would appreciate thoughts on next steps to try. Thanks
Expert:  A. Penland replied 2 months ago.

I think it is the dash fuse box, but let me run this past a Ford engineer friend of mine in Dearborn. He has access to a it more information than I do at a Ford technician level. I will need to send him an email. I will also need the mileage. A rough guess. Does not need to be accurate.

Customer: replied 2 months ago.
198000 miles. VIN 1FMPU15L13LC29667 if that is helpful. Thanks again.
Expert:  A. Penland replied 2 months ago.

I'll put the email out tonight. I will not hear back from him till tomorrow around noon.

Expert:  A. Penland replied 2 months ago.

Also, did you leave the fuse #14 out and then drive the vehicle till it happened again or did you put fuse #14 back in?

Expert:  A. Penland replied 2 months ago.

Do you have a trailer harness on the rear of the Expedition and if so. is it factory or aftermarket like from U-Haul?

Customer: replied 2 months ago.
I took out fuse 14 for testing but put it back in. I can leave it out for a little while if you would like.
The truck has a trailer harness - it is the factory harness.
Expert:  A. Penland replied 2 months ago.

This is going to need a hands on electrical technician. It is a little drawn out to be doing online.