Engine will not start-Blows Fuse: 1994 Dodge Grand caravan 3.0L 134K miles

[Chaud]

Some background first: One day Van Transmission went into Limp mode ( Stays in 2nd gear Only). Found out " Engine system" fuse was blown. Replaced the fuse everything became normal for an hour or so of driving until the same fuse blows again and limp modes kicked in. Fuse was replaced five to six time to get the car going. One day, the new fuse will blow immediately as soon as the legs of the fuse touch the insertion terminals. This looks like a hard short somewhere but don't know where?
This is what I have done.
1. Disconnect the PCM connector , fuse still blows
2. Disconnect the output and input speed sensors plugs on the transmission, fuse still blows.
Is there a better way of finding the short problem rather than hit and trial method as I have been doing? I will appreciate your help if you have any suggestion or solution.
Thanks-Riaz

 

[The old man]

I would take a close look at the dark green/orange wire at the alternator and unhook it . May be a alternator connector shorting out or the alternator itself.

 

[NickD]

Require a circuit diagram as to what that engine system fuse powers.

 

[Chaud]

Thank you. It makes lot of sense. I wanted to do alternator test as you suggested but outside temp. was 15F (too cold) and the wire was not easily accessible. I have to wait until it warms up a little.
Nick D: Electrical Diagram will be nice to have and that way I could check each component connected to this fuse. Until I find the diagram I am thinking I should at least check basic component hooked to B+ directly like Alternator. Other components come to mind are Starter and high tension coil but they only come into play when ignition key is turned on.But the fuse is blowing without the key on. So Alternator is highly suspected.

 

[kev2]

I will try to add a diagram-

the circut fuse is under hood? called engine system on legend ? often printed on box cover OR owners manual, there is going to be several diagrams and want to add correct one - anything to narrow down the hunt

Tell us vehicle is STOCK- no add ons modifications - CEL has been OFF before this problem?

 

[The old man]

My understanding that this fuse was blowing when you turned the ignition on. I misunderstood. The fuse that I was talking about was a 15 amp fuse that was labeled "Engine Fuse" in the power distribution center under the hood. It fed the ASD shutdown relay. It would only affect the Alternator if the ASD relay was energized with the ignition switch. The only way power would get to the Alternator when the ignition switch is off, would be if the ASD relay contact are shorted closed at times. Like kev2 said, we need to know what fuse you are talking about and where it is located at and a number of the fuse if you have it in order to get the correct diagram. I will put here what I have on that diagram, It may be hard to read, but my printer is not rear clear lately. And it might not be the right diagram, but let us know. kev's drawing may be a lot clearer than mine.

 

[NickD]

Do not recall hearing the term "polar vortex" before but know what it means. Like -27*F here this morning, but suppose to warm up to -1*F. Is this vehicle sitting outside?

Wife and daughter are stuck in Colombia due to severe storms in the NE US with over a thousand downed aircraft. Weather there is fine, but no planes. Heard of electric grid lock, but also have aircraft gridlock as well.

Pulling that automatic shut down relay would be a good start. Test lamp made with a directional signal bulb will save a lot of money on fuses. With 22 AWG wire and wrap the base of an blown fuse with a touch of solder, other ends to the base of the bulb and one of the terminals.

Plug that in, when this light goes out, you have found your problem.

 

[Mobile Dan]

Is this the correct fuse box?

 

[Chaud]

Thank you all for helping me out. Here are the answers to some of your questions.

Kev2: The fuse box is underhood and next to battery, After taking the cover off, I saw 6 fuses on the right and relays on the left. Below the relays there were a row of some other fuses. Inside of fuse cover had the legend and components placements but no diagram.
statement below
"vehicle is STOCK- no add ons modifications - CEL has been OFF before this problem? " is correct.

NickD: Thank you for your great suggestion. You have saved me some money. I wish I had this gadget before blowing $20 worth of fuses.

 

[kev2]

did DAN show the correct fuse box in his post?

 

[Mobile Dan]

Chaud, I posted a pic of (hopefully) your fusebox so that it would be easy for you to identify (and tell us) which fuse is blowing. Is it the one labeled ENG?

 

[Chaud]

Thank you all.
Dan: The fuse box pic looks similar but to be 100% sure I have asked my son in Utah to send an actual pic from the van. I went there to see him during the holidays. I intend to go back as soon as I find out what to look for. I have circled the fuse which blows all the time.

 

[kev2]

Its raining so I am looking over the wiring diagram...

the fuse blows as soon as put in - key in pocket? not in run or accessory ?

you unplugrd the PCM and the alternator lets try removing the ASD relay I do not think it will matter BUT gets me thinking.

it appears cavity #3 is the power cavity #4 is the load, cavity #4 goes 2 places PCM and ASD -

GTG

 

[Chaud]

Well, I have the actual picture of the fuse Box. Dan can identify if it is the same or different compared to his earlier post. Btw Kevin, I only took PCM connector off and did not touch Alternator at all. We are getting close to nailing down the problem and I very much appreciate everyone's time and effort.

 

[Mobile Dan]

Since the ENG fuse and ASD relay are both located in the PDC, it becomes much more likely the the red wire(with white tracer) is shorted to ground somewhere between the PDC and the PCM.