No Power at my fuse?

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Mar 17, 2011
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98 Expedition 5.4
I have checked my fuses and I cannot get test light to read power at the DTR Sensor Fuse on either side of the fuse.
Fuse 21. There are others with that same condition.
What could cause this issue?
Fuse is O.K, just no power at the fuse terminal
 
Is it supposed to be constantly hot, or is there another relay or something upstream that must be on before you get voltage at this fuse?

Is it switched or unswitched (key)?
 
Power is not reaching the fuse. I'm not familiar with the circuit or schematics, but whatever feeds this fuse is not sending power or you have a wire break somewhere.

Are you able to see behind the fuse center? Check for a loose or broken wire. Are both terminals which the fuse pushes into fully inserted into the fuse block?

What is the "DTR" sensor? You might need to get ahold of the wiring schematics and see what feeds the fuse.
 
I did test it with the switch on and running.
Not sure about what feeds the fuses on this circuit.
I am troubleshooting a problem (posted in a different subject). The problem stems from a probelm where my truck tries to stall when shifting into gears and the concensus is that it has something to do with the digital range sensor on the transmission...this could make sense, if there is no power in or out of that circuit, then it couldn't do its job.
Just trung to find out how to troubleshoot where the power comes from on this circuit, so I can chase it.
 
Fuses aren't necessarily powered all the time, and can even fed from controllers when ever a controller needs to check something. The fuse may not even see 12V depending on the situation. I'm trying to find out more about the circuit.

DTR sensor is Digital Transmission Sensor, which I understand reads what gear range (gear commanded) the trans is in. I see it is used as an interlock to start, in which it only allows current to flow to the starter relay if trans is in P or N. But it may facilitate other functions as well.
 
If it is a power fuse for a sensor, it should likely be supplying the sensor at all times during key on. Digital sensors are usually all 12V as well.

If I was at home I would go run out and check if I had power there. Maybe someone else could do this quick. I'm sure that's your problem, but I'm not sure where the fuse is fed from. Its likely fed off a power splice back in the harness, or the splice may even be in the open behind the fuse center. Sometimes there are bus bars which run across one side of multiple fuses supplying the high side to each. The first thing I would do is get access behind the fuse center and look, maybe even snap some pictures of exactly what fuse and post it up here.
 
Thanks,
I disconnected the DTR Sensor and did have a no start situation and then started when reconnected.
I did test the fuses while shifting gears as well, still no power and engine RPM's decrease when shifting from P or N into gears, mostly when shifting into R and L1.
Is there a way to test the electrical on that circuit? Or do you see that there is something before the fuse that I should test?
Keep in mind that I have the same situation on the following fuses
16,17,18,20,21,26,27,28 and fuse 7 in the mini fuse panel in the engine compartment.
 
Ah, see above I edited my post well after you posted.

Yes, now that you mention all the other fuses in the same vicinity, I would guess they are all supplied by the same source (which could also be a fuse somewhere, likely larger than the rest).

Are you seeing any other trouble related to what these other fuses power? Most fuses in a fuse center should have power to them at key on.
 
Thanks so much for taking the time here.
I think you are on to something...I checked the other fuses and there was a couple obvious ones that I could see working. For example, the hibeams and fog lights. It is apparent that they are fed by a relay, soo when I turn on the fog lights it powers up the fuse and vise-versa.
Is it possible there is a relay on the circuit for fuse 20 and 21?
 
What is fuse 20?

I would think a Digital Trans sensor would be supplied all the time. Have you tried to get behind the fuse block to look at the wiring? My guess is the circuit path is not making it to the fuse.
 
Well, maybe the problem is not electrical after all.
I found that power is supplied during starting process only to those fuses.
Thanks for taking the time with me on this, you help me a lot.

I guess I have to look at some other cause for my problem with engine trying to stall when shifting from Park or Neutral into R and L1.
 
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