Electrical starting issue
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Mountain Pass
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Electrical starting issue
2004 F550, 6.0. When I turn the key I get nothing at all; not a click, clunk or even dimmed dash lights. When I remove the wire on the passenger side fender that goes down to the starter and try to jump it directly from the battery by touching it to the positive terminal the truck cranks as normal. Other than the ignition, where else should I look to determine the problem and how do I test the components. Thanks all.
Fleet Owner
Joined: Nov 2003
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You can also turn the key to the "ON" position and then put the truck in reverse - are the reverse lights coming on?
When you remove the secondary fuel filter from the housing (and remove the standing fuel), how long does it take to fill the housing with fuel when you turn the key to "ON" (two person test since it should fill quickly)?
Also check fuse F2.22 (#22 in the CJB).
When you remove the secondary fuel filter from the housing (and remove the standing fuel), how long does it take to fill the housing with fuel when you turn the key to "ON" (two person test since it should fill quickly)?
Also check fuse F2.22 (#22 in the CJB).
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Mountain Pass
Joined: Jan 2009
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Thank you.
Fleet Owner
Joined: Nov 2003
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You don't really have a neutral safety switch. You have a Transmission Range Sensor. It is not a simple switch. The PCM gets involved.
If you want an easy way to know if it is working (the TRS), do what was recommended above with the shift lever in reverse.
Your PCM grounds the starter relay when everything is ready for the starter operation. The PCM also grounds the fuel pump relay. If you want to know if the PCM 12V power circuit (PCM logic) is "probably" good, then a checking to verify that the fuel pump is turning on with the key is a good way. Lots of people say they hear the fuel pump turn on, when it is really the vacuum pump, so I ask to get visual confirmation that the fuel pump is turning on even though that part isn't really necessary.
Shorts in wiring (especially to the fan clutch) can drag down the 12V buffered power and cause the PCM not to activate the grounds for starting and for the fuel pump. It can also interfere with the output of the TRS.
Easy tests. Your call.
If you want an easy way to know if it is working (the TRS), do what was recommended above with the shift lever in reverse.
Your PCM grounds the starter relay when everything is ready for the starter operation. The PCM also grounds the fuel pump relay. If you want to know if the PCM 12V power circuit (PCM logic) is "probably" good, then a checking to verify that the fuel pump is turning on with the key is a good way. Lots of people say they hear the fuel pump turn on, when it is really the vacuum pump, so I ask to get visual confirmation that the fuel pump is turning on even though that part isn't really necessary.
Shorts in wiring (especially to the fan clutch) can drag down the 12V buffered power and cause the PCM not to activate the grounds for starting and for the fuel pump. It can also interfere with the output of the TRS.
Easy tests. Your call.
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Mountain Pass
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Fleet Owner
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With no reverse lights, you have an issue with the Range sensor or its electrical circuit. without that information, the PCM will not throw the ground for the starter relay.
Have you checked fuse 22 under the dash?
Have you checked fuse 22 under the dash?