OD Shenanigans
09-29-2012, 10:35 PM
#16
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Well I took it to a Tranny shop this morning All the way there the OD bypass switch hooked up worked and it would go into OD but it was cold. The tranny shop put it on a scanner and told me to check the wiring. Brought it home dropped the pan and changed the filter and fluid. Everything was tight , no lose OD solenoid. I checked the blue wire going to the OD solenoid again and it was going from 13 volts to 0 volts to 5 volts. I am guessing that the blue wire should have 13 volts constantly when the truck is running. And that is why my bypass switch is intermittently working If thats true where does that blue wire go? I am unable to find it when it goes up above the tranny. Thanks for all the help!!
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92 W250 LE Regular Cab
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92 W250 LE Regular Cab
Likely the connector crimp is loose on the wire, or the wire is broken near the connector. Of course it could be broken anywhere along it's route from the firewall.
I nailed this item as the first (most likely) thing to check in post #2. I strongly recommend that you get the shop manual with the correct wiring diagrams and learn to read them. It'll make shooting a bug like this a 10 minute deal instead of all the hassle you've endured.
09-29-2012, 10:39 PM
#17
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Where do I locate the A21 Splice or the correct connector, Any pics would greatly help. I looked but was unable to locate the connector on the firewall.
09-30-2012, 07:28 AM
#18
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As I said, the spices themselves seldom fail, but wires get brittle and break, usually near connectors, but also at other stress points. Door wiring, for instance often fails in the flexible conduit in the door hinge.
09-30-2012, 07:47 PM
#19
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Spent some time checking the wiring after work. I checked the blue wire and it was holding 13v with the key on, opposite of yesterday. I checked the blue wire in multiple points while moving all the wires to check for a broken wire. I was unable to replicate the fluctuating voltage I had before.
Does the wire go through anything else that could be bad? PCM? Ignition switch? Relay on the fender?Any Ideas??
Does the wire go through anything else that could be bad? PCM? Ignition switch? Relay on the fender?Any Ideas??
10-02-2012, 11:03 AM
#21
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Spent some time checking the wiring after work. I checked the blue wire and it was holding 13v with the key on, opposite of yesterday. I checked the blue wire in multiple points while moving all the wires to check for a broken wire. I was unable to replicate the fluctuating voltage I had before. Does the wire go through anything else that could be bad? PCM? Ignition switch? Relay on the fender?Any Ideas??
Does the wire go through anything else that could be bad? PCM? Ignition switch? Relay on the fender?Any Ideas??Believe it or not, the most likely point of the break is right at the crimp on the connector. If it is loose, wiggling it might brighten up the connecting point till it looks good.........for now. Usually with a little gentle tugging you can feel the looseness.
10-02-2012, 12:45 PM
#22
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Couldn't I just run a new wire from the fusebox that is switched from the ignition to the OD solenoid and cut the existing wire and bypass everything and use my switch to ground it when OD is needed?
10-02-2012, 09:08 PM
#23
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Still think it's just a bad crimp on the connector.
10-02-2012, 10:00 PM
#24
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I know NOTHING about this particular wiring loom, J. Martin does, and good advice there! But: in some many years of automotive & other electrical troubleshooting I find the single most common culprit is bad GROUNDS!
Every circuit eventually runs to ground. Clean, tight bare-metal grounds all through the system are critical to completing circuits and a bad one can act as an intermittent gremlin again & again to drive ya nuts. Also they're usually the easiest to get to and check first.
Every circuit eventually runs to ground. Clean, tight bare-metal grounds all through the system are critical to completing circuits and a bad one can act as an intermittent gremlin again & again to drive ya nuts. Also they're usually the easiest to get to and check first.
10-10-2012, 08:51 PM
#25
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Finally had a chance to work on the truck. I checked the wires by grey and black connectors, wires looked fine. I wired a new lead to the OD solenoid from the heater relay as suggested. I was unable to locate any of the ground wires other than the main one on the front by the radiator. Took the truck for a drive on the highway and same as before it has no issue at first, I go a few miles and everything works great, get off and turn around and it goes in and out of OD. Flipping the switch I have going to ground from the other side of the OD solenoid makes no difference it continues to go in and out. I am thinking the OD solenoid is the culprit. Any other possible reason besides that?
10-14-2012, 08:41 PM
#27
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