Where Is IOD Fuse

Tiny
ANGELSDOFLY2
  • MEMBER
  • 1991 DODGE CARAVAN
  • 6 CYL
  • AUTOMATIC
  • 111,550 MILES
1991 Dodge Caravan IOD Fuse
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Monday, August 1st, 2011 AT 8:18 PM

10 Replies

Tiny
CARADIODOC
  • EXPERT
Look at the rear of the under-hood fuse box. As I recall, it may be in a yellow pull handle.
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Monday, August 1st, 2011 AT 8:31 PM
Tiny
JDL
  • EXPERT
I'm not aware of IOD fuse on this vehicle. I didn't see it in your fuse box?
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Monday, August 1st, 2011 AT 8:44 PM
Tiny
JDL
  • EXPERT
Hi caradiodoc, didn't mean to butt in, didn't see you. MOD didn't show an underhood fuse box? Have a good day.
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Monday, August 1st, 2011 AT 9:01 PM
Tiny
ANGELSDOFLY2
  • MEMBER
Ok, I have flashing instrument lights, radio works, cassette player works, clock is fine. I have no speedometer, no temp guage. It drives fine but keep flashing on and off. Lost the Fuel guage this morning. Any ideas?
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Monday, August 1st, 2011 AT 10:30 PM
Tiny
CARADIODOC
  • EXPERT
Hi JDL.

The symptoms don't match exactly but there was a problem in the '92 models with the Body Computer. It would lock up due to voltage spikes resulting in loss of dash lights, gauges, chime, interior lights, and I think door locks. I suppose that could affect a late production '91 model, but I'd be real surprised if that problem wasn't taken care of a long time ago. The computer could be reset by disconnecting the negative battery cable for half a minute, but the problem typically reappeared within 5,000 miles.

The permanent fix was to replace the Body Computer with one that was less susceptible to voltage spikes, and to replace all relays that didn't have spike suppression built in. There could be up to 12 of those relays but I usually found only four to six. They are located by the fuses inside the van, under the steering column, and they have part numbers that end with a "1001". I think you have to remove the "knee blocker" to get to them. That's the thick panel under the steering column.

I don't know if Body Computers were used yet in '91. If it was, once that knee blocker is removed, the computer can just barely be seen slid in to the right and under the radio. It slides out to the left toward the steering column after removing one or two screws.

If there's no IOD fuse in the fuse box under the hood, (or if there are no plug-in fuses under the hood), look for a smaller cable leaving the battery positive post. It will have a bullet-type connector about a foot away from the battery. That is disconnected when the vehicle is going to be stored for more than three weeks. It removes voltage to all of the computers to prevent their memory circuits from draining the battery. Many functions will not work, but the engine will start and run and some features such as power windows will work while the engine is running. The delivery truck driver can operate the vehicle safely without having to plug that cable in.
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Monday, August 1st, 2011 AT 11:06 PM
Tiny
ANGELSDOFLY2
  • MEMBER
Ok, I did all the above nothing worked. But when I got into the seat, I knocked into the lower part of fuse box from interior lower drivers side. When I did, all the lights flashed on. I took the fuses out all good. I checked again. So is there a major connection or am I looking for a wire? Thanks
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Tuesday, August 2nd, 2011 AT 2:04 PM
Tiny
CARADIODOC
  • EXPERT
"I knocked into the lower part of fuse box"

Do you mean you looked in the fuse box or you banged it? If moving it in some way made something start working you know there's a connection problem. It's impossible to say where that connection is without being right there to diagnose it. I'd start by unbolting the fuse box then looking on the back side. There will be a bunch of brass strips connecting many fuses together and each strip will have a wire feeding them. Look for loose wires or a loose rivet connecting multiple strips. If something loose isn't real obvious, wiggle wires until things start working and / or you see tiny sparks or arcing. Also look for a small black spot indicating arcing was taking place. If you see a spot like that you might get away with squeezing a crimped connection tighter, otherwise soldering the bad connection should solve it.
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Tuesday, August 2nd, 2011 AT 6:23 PM
Tiny
ANGELSDOFLY2
  • MEMBER
Ok with the panel off, I see that the fuse box? ( Plastic encasement with two screw has been broken off where the screws are)these are the fuses I checked earlier and found them to all be good. I touched it to pull it back in place and got a nice shock. Key is out of ignition now and I came in house after that. Should I undo the battery before I look again? Never want to feel that sizzle again!
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Tuesday, August 2nd, 2011 AT 7:43 PM
Tiny
ANGELSDOFLY2
  • MEMBER
Well, I didn't here back from you but we found that everything started working again, I have not done anything to fuse box as of yet. But we did replace the thermostat and sensor. They said thermostat was bad. I still think there is short in the back of fuse box, or with the heat caused something to spike. Forgive me, I am female with little knowledge of repair but really wanted to help my father since he is recovering from pacemaker placement. I do appreciate your time and efforts. Thanks
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Thursday, August 4th, 2011 AT 10:50 PM
Tiny
CARADIODOC
  • EXPERT
Sorry. My internet service was out for an entire day, ... Again!

Just to put your mind at ease, you can't get shocked from the car itself because it runs on 12 volts. That's not enough to feel. What you CAN feel is if something with voltage touches a metal part that is grounded to the body. That can make a big spark and heat. Also, you can feel a tickle if you touch anything tied to a coil when the voltage is removed. That creates a voltage spike, the same way an ignition coil works but sometimes that spike is also too small to feel. Those coils of wire are in relays and motors.

I'd be looking behind that fuse box to see what's going on. It sounds like there's a loose connection. Watch whatever goes dead while you move wires and push on those brass strips. Also watch for little sparks. Those will occur at the location of an intermittent connection
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Thursday, August 4th, 2011 AT 11:26 PM

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