How do you replace the passenger compartment fuse block in a D2?

[PhD_Polymath]

Hello,

I tried searching around in this forum and others to make sure I understand how to replace the fuse block mounted under the steering column of my Discovery 2. It seems like simply unplugging the old one and plugging the new one into the harnesses is all the replacement entails. However, I am concerned about the IDM (Intelligent Driver Module) that needs to communicate with he BCM (Body Control Module, or is it Unit?). I read that the IDM is integrated into the fuse block and when replacing fuse blocks, one needs to set the ignition on (not trying to engage the starter) and leave it for 5 minutes to allow the IDM and BCM to communicate and prevent immobilization.

Here is my logic on replacement steps:

1. Open driver's door using key in the handle to unlock (I do not have keyless entry, as the fob never worked since I bought the truck). Open access panel under the steering column to access the fuse block. Do not remove the nut securing the block at this time, as this may result in possible shorting.

2. Leaving the driver's door open, pop hood.

3. Remove negative battery cable from battery.

4. Leaving hood open, remove nut securing fuse block to lower it from it's location and remove harness connections from the fuse block.

5. Connect harnesses to the new fuse block and reinstall to completion (place block in proper location, tighten nut that secures it at the top, close access trim panel under the steering column).

6. With the driver's door open, reconnect negative battery cable.

7. With the hood still open, place key in ignition and turn on the ignition (not all the way to the start position, though). Let sit for 5 minutes undisturbed.

8. Turn key to start position and hope for the best.

9. Close hood and hop in and close door. Let truck idle until up to operating temperature. Try the heat and see if the fuse block fixed the blower motor problem.

10. Shut off ignition.

11. Restart the truck to verify all is well.

Sorry if it appears I am overthinking this. I just don't want to end up needing a Testbook or Nanocom to bail me out for hundreds of dollars if I am missing something important. I do not have keyless entry fobs for this truck and it doesn't seem to care even when disconnecting the battery, but am not sure if I need some keyless accessibility after swapping the IDM. Thanks in advance for any advice.

 

[PhD_Polymath]

Well, I changed the fuse block as written. I had a used replacement that appeared to be in good shape. The fuse block had connectors exactly like my original one, but the placement and appearance of a couple relays were slightly different. After hooking the battery up, I heard chiming like when you leave the key in the ignition with the door open. The rear wiper was moving slowly as well, even though I hadn't pushed the switch. I heard a "pop" and the wiper stopped (as I suspected, later investigation revealed the fuse had blown). The alarm light was illuminated and I was sweating bullets for 5 minutes. The light went out and I started the truck. For the first time in a month, the heat worked! I was excited, as that was the reason for replacement. I shut off the engine and noticed the gauge lights stayed on. The headlights were off... I shut the door and locked it, thinking maybe the gauge light would go out with the dome lamps. No, that did not happen. I dimmed the gauge lights all the way and that worked, but I knew that would not work as a solution. I don't want a dead battery. I was going to go for a quick drive and noticed the radio and clock both were non-functional. Deciding the replacement fuse block was a bad idea, I put my original back in. Now everything works, except the rear wiper and of course the heater blower motor. The wiper just blows fuses, so I am thinking I may have blown a relay or melted a wire. Dang.

 

[superbuickguy]

when you replace parts, especially fuse panels, on a D2, you need to be certain it's the same year and same equipment - otherwise problems will ensue (this is true for lots of vehicles, actually).

 

[PhD_Polymath]

I just did a quick search online. I had requested a fuse panel from a 2000-2002 discovery 2. I was sent one from a 2003-2004. Apparently, even though they both plug in, they are not the same thing. I am just happy nothing worse happened, like not being able to start the truck after going back. I just hope I can swap for the correct part.

 

[BirchHill]

Here is how I fixed mine without changing the fuse block. Copy and pasted from some ones write up.
Like some on this forum, I had an intermittent working blower that finally died. One of the fixes (for some) from past threads was to install a new fuse box. Somehow the connection through the fuseblock to fuses 6 & 7 fails. Fuse 6 (25 amp) is rear A\C blower, if equipped, and fuse 7 (30 amp) is the front A\C blower. Both of these were dead on mine as well.

I looked at the engine bay fuseblock, also. Fuselink 4 was good, however, the connector (on same fuseblock) it sends power to was dead at the Brown\w Pink wire. This wire goes to fuses 6 & 7 in the passenger fuseblock.

I ended up running a bypass wire to each fuse directly from fuselink 4 (cold side, next to side of fuseblock), with an individual blade fuse holder on each wire. I put a spade connector on the ends and tried plugging in to the cold side of slots 6 & 7. It still didn't work. This fuseblock was bad, also.

I pulled the fuseblock and attached directly to the wires out (cold side) on the back. For fuse 6 (rear blower) pull connector 585, first in line, brown with three wires. You want the Yellow\Green wire. Pull the white retainer clip and dig out this wire with a small screwdriver. It has a spade receptor, of which I attached my 25 amp bypass wire. Put clip back and replace connector. The next connector back is 584, pull it. It is also brown, but has five wires in it. You want the Brown\Red wire. Pull it out the same way. I connected it to the 30 amp bypass wire. Fix and replace the connector. Button everything up.

Success! I now have cold air blowing, front and back. Less than $20 for wire, individual fuseblocks, and connectors.
Attached ThumbnailsA blower problem fixed!-fusebozback.jpg
Attached Fileslink4.pdf (48.3 KB, 23 views)
It is usually a faulty interior fuse block, specifically at the blower fuse. Between the wire harness connector on the back and the fuse on the front, there is a break in the power supply through the block. You can replace the fuse block, or bypass the block altogether, like I did, and run a independent fused wire to the blower.

The resistor pack can go bad, however, if the max speed fan setting doesn't work, then it is not the resistor pack. Max fan speed bypasses the resistor pack. There is a different rated resistor for each slower fan speed.

Note: Both of my fuseblocks (interior and under the hood) were dead for the blower circuit, and I bypassed both. See the attached images in the linked thread. __________________
The drawing is of the engine bay fuseblock near the battery.

As for the interior fuseblock, check fuse 7 for power with a test light (with A/C on).

If you have power at the fuse, remove the nut at the top of the fuseblock, pull the top of fuse block down to reach the back. Pull connector 0584 (see photo), locate the brown with red wire. From the location of that wire in the connector determine which pin on the fuseblock that wire attaches to. Check that pin for power from fuse 7. If you don't have power then your interior fuseblock is bad (not sending power from fuse 7 to the rear connector). Buy a replacement fuseblock, or bypass it like I did (see below). If you have power on this pin, then either the voltage is less than the blower needs to run or there is a loose connection/cut wire.

If no power at the fuse, remove the nut at the top of the fuseblock, pull the top of fuse block down to reach the back. Pull connector 0581 (see photo), locate the brown with pink wire, test this wire through the connector with the test light (with A/C on). If you have power then your interior fuseblock is bad (not sending power to fuse 7 from the rear connector power supply).

Buy a replacement fuseblock, or bypass it like I did.The wires in the connector are locked in with a thin white plastic plug. Pull this plug out with needlenose pliers, take a small flat blade screwdriver and dig/pry the brown with pink wire out. It will already have a spade bit receptor attached.

Do the same for connector 0584, for the the brown with red wire (This wire is direct to the blower). Buy a 30 amp inline fuse, attach spade bit tips to both ends of the 30 amp inline fuse and plug into the 2 wires you dug out. The blower should work now.

If you don't have power at the brown with pink wire (connector 0581), then you need to check the engine bay fuseblock (see drawing in linked thread provided earlier). Power starts at fuselink 4 and exits the fuseblock at the connector shown through the said brown with pink wire.

 

[PhD_Polymath]

Thanks for the bypass info. I should have mentioned that I tried to do the bypass on my fuse block. I tried in vain for 2 hours to get the spade connector out of the plug after removing the white piece. The spade connector was not coming out even after completely removing the white piece. I tried digging with a tiny flat blade screwdriver to no avail and just buttoned it back up so I could drive it. Am I missing something? Perhaps there is a tab that requires a special motion for removal? I had purchased the in line fuse holder and would be happy to use it. I thought about cutting the wires and splicing, but I hate to make such poor repairs that can't be easily undone and with what little wire is accessible, I feel that would be the case if I resorted to splicing. On the other hand, the spade connectors being used with an appropriate in line fuse lead would be clean enough that I wouldn't worry about it. Thanks again.

 

[PhD_Polymath]

I just spoke with the guys that sold me the replacement fuse block. They are sending the correct piece free of charge. To boot, they didn't even request the old one be returned. Stand up guys to do business with and I am sure I will continue to be a repeat customer. :wings: