attn XR7 Dave-melted fuse for ircm problem

kws6000

Registered User
Hey Dave,hope you had a good trip home.Too bad this didnt happen when you were in Calgary.

Went for a drive today( in my 95 sc auto) and the cooling fan wouldnt turn on.

Checked the under hood fuse panel and 60 amp fuse for fan control module was blown and partially melted in place.

When I pried it out,one of the spade terminals in the fuse box came out also.

When I looked underneath where the wires enter the fuse block,the wire for this terminal was charred near the end and had melted into the white plastic.

Fan turns freely ,no other signs of overheating in the fuse block.IRCM shows no signs of overheating.

I am at a loss as to what caused this .
 
They all do it. My 94. Ira's 95. My suggestion... get a a couple of relays, fusable links, and thermo-electric switches, and rewire the fans to run independant of the EEC before you end up melting the power distribution box and wiring like I did.
 
I never had that problem however a short in the fan motor could definitely cause that to happen. Hotwire fan to see if its functioning and work from there
 
Most likely the issue is caused by the high current draw the fan takes and a poor quality connection at the fuse itself. Perhaps some dirt got in there, or a piece of something on the fuse blade was preventing full contact or the clip the fuse plugs into was bent so it wasn't contacting across it's full length.

The point connection heats up due to the load across it and if the full blade isn't used for the connection it easily will exceed the heat rating of the wire and the plastic the fuse is mounted in.

That's the most likely issue. Others could be corrosion in the wires close to the connection, maybe the crimp joint at the fuse lug on the wire preventing the wire from carrying all the load evenly through it's mass, again creating a point of resistance that heats up beyond the rating for the wire.
 
Melted fuse

This seems to be a fairly common problem and not one which is always caused by a bad fan motor. My 95 was doing the same thing and there wasn't anything wrong with the fan, the problem was caused by the poor conection between the spade terminals of the fuse and the fuse box. To repair mine I removed the wires from the fuse box and installed a 60 amp fuse that has eyes on each end so that the wires could be bolted to it. It has been that way for the last year and I haven't had any other problems with it, and it still works just the way it did from the factory except that it doesn't get hot and melt.
 
Agreed. The fuse connection is poor. I didn't think about it when we were working with the car. Most likely the more aggressive fan settings engaged the high speed circuit more than normal and increased the load on the circuit. Check both fans to ensure that they both work. Sometimes the pusher fan will lock up due to not getting used often with the stock fan temp settings.
 
XR7 Dave said:
Agreed. The fuse connection is poor. I didn't think about it when we were working with the car. Most likely the more aggressive fan settings engaged the high speed circuit more than normal and increased the load on the circuit. Check both fans to ensure that they both work. Sometimes the pusher fan will lock up due to not getting used often with the stock fan temp settings.

What is the best way to check the fan operation?

Is the ircm a possible issue?

The replies here suggest the problem is exclusive to the 94-95s.Has this happened to any earlier model cars?
 
check the fan first..Hood direct power to it..Posative negative..If the fan works then look elswhere sush as the fuse connection and lastly the IRCM. Fan should be teh first thing to check IMO..Then liek I said..take it from there
 
Ken,

Once I get the brakes restored on the explorer (i lost them completly coming home the other night), I'll wander up with a bunch of electrical stuff and we'll go over your car again. Give me a shout.

Scott
 
Fuse1-full;init:.jpg

Fuse2-full;init:.jpg

Fuse3-full;init:.jpg


Must have gotten pretty hot, you can see the track where the wire melted the plastic!
 
Tom/Ken

I'll stop by on sunday and see if we can't rig up an external fuse. At the same point, I'll write up a how-to to post online.

Is there a pusher fan on late SC's? I guess this could also cause the excess draw compared to the early models.
 
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Am I correct in assuming that to bypass the fuse block ,you extend the wire originally going to the burnt fuse,install an inline 60 amp fuse and connect it to the pos side of the superfuse?
 
Not exatly. What I did was run power directly from the battery to the fan and control the fan with a thermo-electric switch.

You'll need some decent gauge wire, a 30A relay, an in-line fuse (60A), and the switch. I don't have the wiring diagram handy, but you run the wire from the battery to the fuse, fuse to the relay (which is triggered by the switch), and relay to the fan. You can get the switch's power from any key-on source.
 
kws6000 said:
Am I correct in assuming that to bypass the fuse block ,you extend the wire originally going to the burnt fuse,install an inline 60 amp fuse and connect it to the pos side of the superfuse?

That is correct. Finding an "incognito" way of doing it is the hardest part. :cool:
 
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