Help with PCM fuse that keeps blowing Electrical Issue

Toolsplusmore said:

Hotcobra, I will check those two connectors when I get back home. The only part I am not sure of is that when you unplug those connectors aren’t you breaking the circuit at that point so the fuse can’t blow? At that point it would always show open correct? Regardless I will unplug both when I get home and will post he results.

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you are trying to get fuse not to blow.when you turn key.
just like you tried already with unplugging some of the items..or say component.

c133.pin 9

is circuit 361 coming from pcm relay,
to engine sensors..

if short is after c133.. pin 9 should stay hot with key on.and fuse 26 not blow.

c1045 is the other.361 does not run thru that..

if fusee blows with c133 unplugged..

look from there to ccrm.

areas we work is the 1st to look at.

just leaning on the harness with elbow,tool dropped,wire pinched ,bad helpers,rodents.

Toolsplusmore said:

Hotcobra with fuse 2 and 8 out the fuse still blows and the circuit tester still shows “short to ground”. It does not matter if both are out or just one it still shows short to ground and blows the fuse.

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Which circuit or pin shows shorted to ground???

Your PCM Power relay checked good by the way.

Hotcobra when C133 is disconnected the fuse still blows, and when C1045 is disconnected the fuse also still blows. Not sure what to look at there.

Jay when I put my power probe circuit tracer into the load side of F26 when the key is turned to run it beeps and shows short / grounded circuit.

Dave, I tested the PCM connector and pins 3,25, and 51 all show good grounds. Pin 55 has 12v all times as it should.

Toolsplusmore said:

Hotcobra when C133 is disconnected the fuse still blows, and when C1045 is disconnected the fuse also still blows. Not sure what to look at there.

Jay when I put my power probe circuit tracer into the load side of F26 when the key is turned to run it beeps and shows short / grounded circuit.

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OK .
follow in wiring diagrams.

ignition 21-3

shows pcm relay output of ccrm pin 24..

circuit1118 14gage wire. red,

goes into c214..see connector views 150-24
this connects 12a581 to 14401

c133 connected harness 12a581 to 12b637..

your ccrm is on harness 12a581
c1262 view 150-61

I'm not on pc to get c214 location.

Chilton site I've been using tonight ,
just won't give it now..I'm thinking this is the connector just below air filter

BlckBox04 said:

I don't want to hijack his thread but is it possible that this would also cut the power and make the gauges sweep during a run? I'm also having an electrical issue, although it's not blowing fuses, in my 2-3 or 3-4 shifts where the car cuts out for a split second then comes back on.

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My guess would be the alternator based on an experience way back in the day with my hci 94. Lost the alternator on a dark backroad. Every time I'd push the clutch to shift the car and lights would cut completely off. Grab the next gear and let the clutch out and itd spring back to life. Did this for a couple miles before i made it back home.

311-420 said:

My guess would be the alternator based on an experience way back in the day with my hci 94. Lost the alternator on a dark backroad. Every time I'd push the clutch to shift the car and lights would cut completely off. Grab the next gear and let the clutch out and itd spring back to life. Did this for a couple miles before i made it back home.

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I actually have a brand new oem alternator in it

Someone else just mentioned checking battery grounds and cables and I was actually thinking that originally also but figured it was worth a shot asking for other opinions

I had to go into my wheel well anyway..

using this tool..

I did a check on both pin 12 and 24 of ccrm..on my car..seeing wiring diagrams bite.

I took off air cleaner and shirt.

I unplugged ccrm,c133,c1045.maf,iat,aux box,than the 2 under air box going to radiator support.

I pull f2 2 and 8..

test..pin24 of ccrm to pin 34 of c133..should go beep all 0s.

than hit all pins in c133 and c1045..

nothing should beep..

pin 12 ccrm to c133 pin9.
wenter beep..

rest of pins no beep but some did read a number other than 1as to meter..shown in pick

Some may not agree with me but that setting is for checking impedance on diodes, a beep does not always mean short for the purpose of checking continuity. One more click clockwise and you will be checking resistance which is what you should be using when looking for shorts to ground.

*Jay* said:

Some may not agree with me but that setting is for checking impedance on diodes, a beep does not always mean short for the purpose of checking continuity. One more click clockwise and you will be checking resistance which is what you should be using when looking for shorts to ground.

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the beep here..is 000 on meter which is what you want to see..

any wire that's touching this wire will also beep..read 000..

last issue on my Cobra..same tool chasing po340..I found it by probing the same way..I got a reading other than 1..
issue was just a stretched wire at connector 1 inch back I probed into wire and got a beep and all 000

this test I did..if I put both fuses back in a get 000 on both pin 9 and 24 of c133..

if any wire in harness is just slightly touching it will pop fuse..it doesn't have to even be visabile

Hotcobra,
I disconnected the CCRM, both C133 & C1045, the MAF, IAT, both connectors under the air box, and pulled both fuses 2 and 8 for engine controls and tested pin 24 of CCRM to pin 34 of C133 and it beeped and showed continuity. Tested all other pins in C133 and C1045 and no other beeps or continuity.

Pin 12 of CCRM to pin 9 C133 also beeped then I tested the rest of the pins in C133 and C1045 and pin 6 (bk/pk 140) of C1045 and pin 35 (bk 1265) of C133 also beeped.

What do those additional pins showing resistance tell us?

Toolsplusmore said:

Hotcobra,
I disconnected the CCRM, both C133 & C1045, the MAF, IAT, both connectors under the air box, and pulled both fuses 2 and 8 for engine controls and tested pin 24 of CCRM to pin 34 of C133 and it beeped and showed continuity. Tested all other pins in C133 and C1045 and no other beeps or continuity.

Pin 12 of CCRM to pin 9 C133 also beeped then I tested the rest of the pins in C133 and C1045 and pin 6 (bk/pk 140) of C1045 and pin 35 (bk 1265) of C133 also beeped.

What do those additional pins showing resistance tell us?

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the 2 fuses in tell me..
pin 24 goes to inside fuse box,and fees those 2 fuses as we see in wiring diagram.
I also get full 000 on c1045 if MAF is plugged in..
so this may not 100% help yet.
the whole harness should be unplugged.
you may have pcm exposed..which I don't to see harness coming thru fire wall..

but even..pin 24 in CCRM is what circuit you are working with..

I have those two fuses out as you told me. I am not understanding your last message, what should I be doing next?

Toolsplusmore said:

I have those two fuses out as you told me. I am not understanding your last message, what should I be doing next?

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meter set like I do.. that pic is just holding ends..i touch them together. meter beeps and reads 0.00

clip on to pin 24 of ccrm.than probe c133.pin34.. you meter should read 0.00 which says I have a connection between..
than probe all other pins in c133,c1045,c1262 and so on..
you should not get 0 on any of them other than pin 34..
if you do..that's the wire grounding pin 24..

this type of test should be done on ccrm harness completely unplugged.

but however at this point you should see the same as I do.

that harness has so many connections..
object here..don't move anything if possible.don't wiggle harness..
if you lose the short you have to wait till next time..

I don't expect you to find wires melted .I expect a splice had probed into 1118.or 1118 into other.
maybe you can post pic of pcm area .I like to see that harness coming into car from fender..

Hotcobra
I think you misunderstood me everything on pin 24 of the CCRM checked out as you described. I am seeing / hearing the beeps clipped to pin 12 of the CCRM.

Pin 12 of CCRM to pin 9 C133 beeped as you explained then I tested the rest of the pins in C133 and C1045 and pin 6 (bk/pk 140) of C1045 and pin 35 (bk 1265) of C133 also beeped and showed resistance.

Toolsplusmore said:

Hotcobra
I think you misunderstood me everything on pin 24 of the CCRM checked out as you described. I am seeing / hearing the beeps clipped to pin 12 of the CCRM.

Pin 12 of CCRM to pin 9 C133 beeped as you explained then I tested the rest of the pins in C133 and C1045 and pin 6 (bk/pk 140) of C1045 and pin 35 (bk 1265) of C133 also beeped and showed resistance.

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ok let's regroup..
1st..I'm on pc in full manual.just today.

what you have found.
pcm relay f26 blows only when relay gets energized.

pin 24, of CCRM circuit 1118 is the out put 12volts..

so something in harness or component connect is cause.

1,,remove all known components along curcuit 1118..
2 completely unhook all ends of said harness..

3,,what's left is just a pile of wires.

4,this must be done to isolate

pg151-23 shows inside kick panel.

unhook the rest of the connections.
c214,c215,c210,c175.
than fender well..it looked like evap and maybe something else..

than it should be just wires .

c214 also has circuit 1118,

let's go back to pin 24..and retest.

pin 24 c1262 to pin 34 c133..circuit 1118

this should be 0s..
pin 24 c1262.to pin 2 c214
should read 0s.

that's it.
test every pin on every open connector..

just 2 thoughts so I don't forget.

if I was testing just harness.and this didn't show results.
I would than put 12 volts to circuit 1118 and than probe with test light.

2.

if you had everything still all hooked up as day 1..
pulling 1118 out of c1262 you could confirm pin 24 stays hot with key on.

ok..I did misunderstand you..

c1045 pin 6 I found Leed to c210,c214..

these are still plugged in..

pin 35 c133..black..circuit 1265..

I can't locate..

now..get this..
c1262 an c175 both have a black 1205..

if c133 is a typo..and is 1205..

you found a short to ground..

OK found it.
see pg 25-7

shield for pcm
ground g201

that is 100% your problem.