update-not solved Or IS IT?! You Decide. See post 60

[93rev2sev]

As far as the harness that the fusable link was on, I stripped it back a little ways and found that it splits into 2 heavier guage yellow wires. The wiring diagram indicated that one of the yellows powers the CCRM and the other one goes to the PCM. With the car off, there is continuity between both of those wires and the yellow at the CCRM

 

[deercrusher]

I have an extra harness layin around - the one that goes to the underhood fusebox and the ccrm and the headlights and foglights and eventually to the ecu.

 

[SHOtime2511]

Id try swaping out that harness.
That could be what caused the fan to burn up in the first place.

Electrical problem suck...
If you haven't already done this,leave the battery disconnected for safety.
I'd hate to see another SHO go up in smoke.

 

[93rev2sev]

Pins 24 (vehicle power) and 8(battery+) are both fried.

 

[St Louis SHO]

I'd say one of those powers is shorted to ground. It may be grounded through any of the ACCY's run by the CCRM, including the fuel pump. Just because you hit it with 12v doesnt mean its drawing too many amps. Although from the sound of what happened, I would be cautious of any work done near the cooling fan.

 

[93rev2sev]

I'm sure it's possible that the FP is pulling too many amps. I'm replacing it either way since I cut the hole and it's right there. Just because I've never heard of a fuel pump blowing up CCRMs, doesn't mean it cant.

Edit: it doesn't look like the cover has ever been off of the tank, so it might be an original 20 year old pump.

 

[jruss1601]

did you try the search button? It's wicked awesome.

 

[frosho]

I totally saw that coming.

 

[sperold]

Find where they took Ernie and get the front harness back.
For all the people who are horrified by some rust on their rockers, I would sooner fix a little rust that face this kind of horror.
Electrical problems are so complex. Good luck on the fix.
This is a long shot. Has this car ever had hood pins? It is easy to nick the harnesses that run under the rad saddle top when you install these things.

 

[93rev2sev]

Ernie (Harwell) is with all the great baseball play by play announcers in heaven. You know...the ones that existed before TV broadcasts became prevalant. They knew to shut up and let you listen to the sounds of the game.

No hood pins ever. But thanks.

 

[sperold]

Oh, I thought Ernie was the 93 on the flatbed... my mistake.
Could you take your smoked CCRMs to a hotshot electronics guru and get answers, you have 2 of them subjected to the same problem, something should be learned by examining them.

 

[sperold]

Can you take your alternator off and have it tested for too much output.
The start of the problem was a battery replacement (sometimes too much output).
When you fixed the little wire, failures happened faster (the output got there in full force).
If you have the nerve to risk another module, put one in and don't start your car, maybe turn the key to run but don't start it. I think your module would be getting your battery power of only 12 volts at this point. If it lives with 12V, then maybe high output supplied by the alternator is killing it.
If it lives with just battery power, try running it without the alternator as a test.

 

[93rev2sev]

I replaced the fuel pump with a new one and I put a blade-type fuse in line to the CCRM so it'll blow fuses instead of CCRMs from here on out.

When it comes time to button this puppy back up (awaiting a CCRM delivery), I'll be disconnecting the fan, A/C compressor, and fuel pump. This will leave only the computer being powered by the CCRM. At this point, I'd better be able to pull KOEO codes. If not, then it MUST be a computer problem, right?

Is it even possible for the computer to be blowing up CCRMs?

 

[NEp8ntballer]

what will cause electronics to fry is a component/components trying to draw too much power to them or a short to ground. fuses are there to save your electronics from themselves.

 

[Winterhawk]

I had this happen to me. If you can't pull the codes and have a no start the little fuse ign. is blown in the engine compartment. there are 2 little one on the ends of the big fuses.

 

[93rev2sev]

I had this happen to me. If you can't pull the codes and have a no start the little fuse ign. is blown in the engine compartment. there are 2 little one on the ends of the big fuses.

Is that the case with a 90? I'm not 100% sure to what you are referring, but there's no power distribution block on a 90.

 

[ScotSHO]

I would compare the A/C clutch coil resistance at the CCRM connector versus an A/C clutch coil on a good SHO and see what the difference is. Then do the same thing on the cooling fan and the fuel pump circuits (if possible). The relative resistance readings should be the same from car to car...

Then check each of those pins to car ground to see if any of them are grounding out (or close to grounding out with low ohm readings).

I bet it is a shorted wire on one of those three loads.

I love working on stuff like this...

 

[93rev2sev]

I love working on stuff like this...

Thanks for the info, that makes one of us.

 

[93rev2sev]

So I got home from visiting the grandson and there's a box at my door. CCRM arrived.

I plugged in a 10 amp fuse, connect the ccrm. So far so good. Unplug the fuse, turn the key to 'on'. Replace fuse "POP".

Unplug the fan.
Unplug the A/C.
Unplug the fuel pump.
Disconnect computer.

Turn the key to "ON"
No pop. The fuse held. At this point, I'm assuming the wiring is OK so I plug in the computer and the fuel pump.
"POP"
Disconnect fuel pump.
"POP"

Replace computer with spare.
No pop. Fuse held.
Plug in fuel pump. It WHIRS! "POP".
Replace fuse with 20A.
Turn key, Fuel pump whirs and it starts. "POP"
Replace fuse with 30 amp and restart car. It runs fo a bit longer and the fuse pops again.

So I got the car started but I don't know what kind of fuse to put in there to replace the fusable link.

Is it normal for that wire to carry more than 30 Amps? Does anyone know the rating on that fusable link?

 

[93rev2sev]

I think I found the answer. can someone confirm?

Sounds like the alternator shorted out. Do an ohm check between the output post and the alternator body, if the is <1 ohm it's toast.

Instead of fuse links get a 6 gage wire and a 150A replaceable in line fuse.