[cmurphy034]

What you're describing isn't an ignition switch problem, it's a problem of power not getting into the fuse block inside if nothing works in the interior. Check the fuses and connections labeled JB Power, if those are fine look at the BCM, and if that's fine look at the connections for the fuses behind the block. If there's something going on in the interior, the pcm might not supply power to the ignition switch, causing your problem. Electrical issues are always a pain, good luck.

 

[InTitusville]

So, the power from the 40A fuse under the hood goes through the BCM then to the ignition switch or does the ignition switch power come from someplace else? If it's the BCM where is it and how do I know it's bad. It's no bid deal for me to replace it but need to know what I'm replacing will get power to the ignition switch. I know the dash works since I put power to it last night and was able to get the odometer and some of the dash indicator lights to come on.

I may try to put power to the ignition switch connector (RUN) output wires today and see if the accessories work. If the accessories work does that rule out the BCM?

 

[cmurphy034]

Ignition switch power should come from that 40a fuse under the hood that's good. If the accessories work automatically when you turn the key, that should rule out the BCM as well as a short in the ignition switch circuit, that would give the PCM clearance to start the car from the BCM. However if you can't get the accessories working without manually putting power to them, the BCM might be your culprit. Also it could be a matter of communication between the ignition switch and the computers, possibly a short circuit if there's no voltage at the switch and before there was. If you turn the key but the computers don't know you did, the accessories won't turn on. If the BCM was bad you would likely have to bring it to the dealer to get reflashed or buy a used one.

 

[InTitusville]

I put power to CAV 3 and 5 pins on the cable and the power windows, roof and radio work. The odometer doesn't come on (tested good when I force powered up the instrument cluster) and the overhead console don't work. I still don't have power to CAV 2 and 4 pins on the cable. I double checked the 40A fuse under the hood and the power to that fuse and both are good. Is there anything else that could be between that 40A fuse and the power to the ignition switch?

BTW... The radio does keep main power. If I turn the ACC power on and off the radio keeps the station but if I pull the battery power under the hood the radio looses the station.

 

[cmurphy034]

I don't believe there's anything in between, if I remember there's no relay for the ignition switch. Did you also check fuses 21, 22 and 31 for ignition run/start? They're three 10 amp red fuses. It seems like everything is working just that nothing happens when you turn the key. If it's not this then I don't know, you might have to start pulling apart individual wires to find a short. Also bad grounds can cause weird things but I don't know if it would cause this

 

[InTitusville]

Fuses 21, 22 and 31 look good. I can't understand why the 40A fuses is good and power to it. Unless there is something between the fuse and the ignition switch it should work. The 4.7l has head gasket issues or more so I'm taking the engine apart this week and that will give me more room to inspect the wiring. Maybe there's a broken wire someplace or maybe I will trace it to something between the 40A fuse and the ignition switch. Stay tuned... If someone does know of anything there please let me know...

 

[InTitusville]

I did some digging and digging and found some ignition diagrams. Then I found some used harnesses on ebay and I can see the under hood fuse panel is a "right side" engine compartment harness. Looks like the power for the ignition come off that harness and goes through the firewall and behind the A/C assembly. Looks like I will need to pull the whole dash apart to pull the A/C assembly out to trace the wires.

Now... This brings us the question in another post I have up... I want to change over from a manual climate control to the dual zone climate control and if I do all this work I'm already most of the way there and need to know if the 2 style climate control under dash harnesses are compatible with the rest of the harnesses in the rest of the Cherokee. I may just try to do the conversion and trace the wires all in the same job.

 

[Uniblurb]

While it sounds like you have a power distribution problem you may want to check the 2 grounds on the right side of your 4.7 engine to make sure they're good/clean.

As can be seen in the below ground write-up G102 & G103 to the rear of the right motor mount supply grounds to the PCM, BCM, (Bus communications), instrument cluster, etc..

http://www.jeepforum.com/forum/f310/jeep-wj-ground-write-up-info-4192594/#post39199282

Also note the G108 ground on the far back inner fender is also a ground location for the BCM.

While I did this write-up mainly from the 04 FSM I also checked the 01 FSM and the same grounds matched up. Not saying bad grounds are your problem but if the PCM or BCM aren't receiving good grounds it could interfere with supplying power to areas you're lacking. Worth checking and good luck.

PS. To access those right side block grounds you may need to remove one of the oxygen sensors if in the way.

 

[Uniblurb]

Not sure what ignition switch diagram you're using but thought I'd post the one from the 01 FSM. Note both 14 & 8 fuses (40a) in PDC are connected to the switch. Also you can see the BCM is connected directly to the switch via the light blue wire.

The ground for the switch, which likely connects the BCM, is the black wire and it can be seen as G200 in the ground write-up diagram link. This ground is on the driver's side of the shifter console under the plastic housing.

Just thought I'd pass this along in case the diagram you're using is different.

 

[Double E]

Don't do the dual zone conversion. That system is not built well and will fail at the blend door and blend door actuator over time. It can be fixed with like parts but fails again. It can be fixed for good with the "heater treater' but it takes away the dual zone feature.

 

[InTitusville]

I checked both 40A fuses for power to the PK/BK and RD wires and both fuses are good and the box has power to both fuses but I have no power at the C1 point. I assume where is says C106 and C200 are connectors and I assume that part of harness are under the dash. I think my next step is to follow the electrical issue is to follow this under the dash harness. I also assume to access this cable I need to pull out the dash and A/C system. The head gaskets are bad so I'm taking the engine apart so might as wall go for taking the interior apart.

BTW... I LOVE that diagrams... Where do you find stuff like that???

 

[InTitusville]

This was the diagram I found.

 

[InTitusville]

I don't mind knowing going in to this there is an issue with the "blend door". I restore 1967 to 1973 Mustang and Cougar in-dash A/C systems and have had to deal with modifications to design problems. I've done over 300 of these A/C units. I know there's a huge difference but I'm sure I can come up with a work around. What is the exact problem with these doors and can I do the conversion with just changing out the A/C & Heater box, harness and controller? From what I see on the 2001 Grand Cherokee you need to take the dash out just to replace the heater core.

In the past I had owned 2 1980 Cherokees, a 1995 Grand Cherokee and we purchase a 1999 Grand Cherokee new.

Don't do the dual zone conversion. That system is not built well and will fail at the blend door and blend door actuator over time. It can be fixed with like parts but fails again. It can be fixed for good with the "heater treater' but it takes away the dual zone feature.

 

[Double E]

(I have a 69 Cougar 'vert!)
It is at KTL right now...


Anyway, as I understand it, the axle that the blend doors ride on over twists the plastic door, breaks the attachment to the axle and allows the rotation to go beyond what it should resulting in a couple of codes including #52 on the ACZ self-diagnostic and the HVAC vent defaulting to defog/defrost mode. I'm not a good reference though as I've purposely stayed away from them until I got my Overland. It's working now but was replaced by dealer previously. When it fails, I'll do the heater treater.

 

[InTitusville]

If you need your in-dash A/C box restored let me know. After restoring over 300 of them I know them inside and out...

This 2001 Grand Cherokee has 84600 miles on it, not bad for 18 years. It has this ignition issue which looks to be between the under hood fuses to the ignition switch which looks like I need to find the firewall connector and test it there and to get to that I need to pull the dash and the A/C system so I may just upgrade the A/C system and try to find a fix for the blend door problem.

(I have a 69 Cougar 'vert!)
It is at KTL right now...

 

[cmurphy034]

There's a mod you can do to fabricate the doors and their hinges out of metal, I've heard it's pretty easy, but I don't know much about it. The AZC system is great...when it works, my right side blows cold air but putting it on recirculation usually fixes that it just takes a long time to heat up.

 

[Uniblurb]

BTW... I LOVE that diagrams... Where do you find stuff like that???

Those wiring diagrams are from the FSM (Factory Service Manual). There may still be a free site around to download them but it's listed as 'not secure' by most all browsers.

Or for $8 you can download the complete digital FSM for your 2001 WJ below.
http://www.pacificcoastmanuals.com/jeep_grand_cherokee_service_manuals.html

 

[Double E]

If you need your in-dash A/C box restored let me know. After restoring over 300 of them I know them inside and out...
QUOTE]
My Cougar had no A/C from the factory. What are we talking about in costs to add it?

That HVAC system in the WJ will need some TLC in the seals and foam insulation that deteriorates as well.

 

[Skerrvydog]

No matter what position I turn the key nothing happens. I thought my ignition switch was bad so I replaced the switch and still nothing. I found a switch diagram and it works. I checked the switch connector and no power. I checked the 40A fuse under the hood and the fuse is good and power to the fuse. What's between the 40A fuse under the hood and the ignition switch that could be bad? The diagram I have shows "Fused B(+)" to pin CAV 2 and 4. I have no power on any of the 6 connections on the cable plug.

Headlights, interior lights, instrument cluster lights, power seets, power locks work, starter, gauges, instrument cluster indicator lights, odometer, power windows, radio are not working.

Reviving this Zombie thread as i chase the same issue - i wonder if Titusville ever found the root of the problem? and thanks Uniblurb for the diagrams and ground write ups