2005 LX470 Main Junction Block Replacement

[jerryb]

I really want to know if it looks something like this.

 

[vcheng]

Any luck getting it open? It would benice and helpful to all the community some info with pics. Thanks!

I really want to know if it looks something like this.
View attachment 1523981

Sorry, guys, I was away. I will report back as soon as I have some time to try and open the old JB, with pictures.

 

[vcheng]

I really want to know if it looks something like this.
View attachment 1523981

So this is what the inside of the Main JB looks like after taking it apart even further:

 

[vcheng]

Continued .......

 

[vcheng]

There are several relays, labeled clearly, one of which is the MG CLT relay. There are only two Denso part numbers, little black ones 156700-1081 and larger brown ones 156700-2411, all soldered directly to the dual-panel circuit board.

Now what?

 

[vcheng]

Any luck getting it open? It would benice and helpful to all the community some info with pics. Thanks!

So I finally did open it further, as promised, posted above.

Now what's next?

 

[jerryb]

Those pics are excellent to have as the newer 100s get older. Thank you. 450$ is probably worth it. Replacing all four in one swoop.

 

[Spike555]

Unsolder the relays and replace them. Thats what I'd do if I was in that situation, he fixed his problem which is great.

Thank you for those pictures, these are very helpful.

 

[vcheng]

Unsolder the relays and replace them. Thats what I'd do if I was in that situation, he fixed his problem which is great.

Thank you for those pictures, these are very helpful.

If I were to replace those relays, I would unsolder all of the old ones, and run wires from the circuit board to an outside relay block like this one:

https://www.amazon.com/OLS-12-Slot-Relays-Installation-Factory/dp/B072KJNPHJ

and mount that somewhere where I would not have to open up the Main JB ever again for a relay replacement.

Luckily, I do not hope to need that repair done anytime soon.

 

[STEVEN XU]

Unsolder the relays and replace them. Thats what I'd do if I was in that situation, he fixed his problem which is great.

Thank you for those pictures, these are very helpful.

Unsolder the relays and replace them. Thats what I'd do if I was in that situation, he fixed his problem which is great.

Thank you for those pictures, these are very helpful.

How can you find those relay in the market to replace the old one?

 

[Spike555]

How can you find those relay in the market to replace the old one?

You Google the numbers on the side of them, then cross reference to make sure you have the correct ones.

 

[sonk76]

The big wiring bundle is held by a large black U-clip that is released from the top. Once that is removed, the entire wiring harness is free from the junction block. The relay block can now be removed by unbolting the two small allen bolts (3 mm):


View attachment 1514810

Would you mind sharing a little more guidance on how to identify and remove/release this "large black U-clip" mentioned above? Couldn't figure out on pictures (or looking at my truck) where this is. Thanks!

 

[sonk76]

Yes, just got it I'll take some pics soon.

 

[vcheng]

Would you mind sharing a little more guidance on how to identify and remove/release this "large black U-clip" mentioned above? Couldn't figure out on pictures (or looking at my truck) where this is. Thanks!

The clip is on the top side of the piece shown in the picture. I assume from your next message that you got it. If not, please let me know.

 

[sonk76]

The clip is on the top side of the piece shown in the picture. I assume from your next message that you got it. If not, please let me know.

Yes, I did find it. Thank you.

Here is a picture of the clip in question, and another picture showing the place where the clip is detached from "above" (the clip is pointing at the point.)

Another detail for others doing the project: you have to remove the top-most relay from the detectable block with all the detachable relays so that you can slide it by about 1/4" in order to release it from the junction block.

Ask more and happy to clarify if helpful.

 

[Crapper49]

The AC portion of the service manual has a troubleshooting section for the "Check AC" message popping up on the display screen. It says to check the magnetic clutch for operation, and if it is okay, to check the AC relay. If the AC relay is acting up, it says "Replace engine room junction block assembly" since the relay is buried inside it and is not replaceable separately.

Okay, I am also having an intermittent AC problem with my 2005 100 series. It started shortly after replacing the compressor and several other parts after a catastrophic failure, to the tune of $2,600.00. The “Check Air Conditioning” indicator comes on, and the AC light is flashing. At first I could just turn it on and off, but now it rarely works. Had my trusted mechanic check everything out and he determined that the compressor and relay were working properly, and it was the multi-function display that was bad. I have since replaced the multi-function display and the AC ampliphier, and the problem continues (I’ve been dealing with this issue for months). Aside from replacing the relay (fuse block), I don’t know what else the problem could be.
Did replacing the fuse block solve your problems? What were the symptoms?

 

[vcheng]

Okay, I am also having an intermittent AC problem with my 2005 100 series. It started shortly after replacing the compressor and several other parts after a catastrophic failure, to the tune of $2,600.00. The “Check Air Conditioning” indicator comes on, and the AC light is flashing. At first I could just turn it on and off, but now it rarely works. Had my trusted mechanic check everything out and he determined that the compressor and relay were working properly, and it was the multi-function display that was bad. I have since replaced the multi-function display and the AC ampliphier, and the problem continues (I’ve been dealing with this issue for months). Aside from replacing the relay (fuse block), I don’t know what else the problem could be.
Did replacing the fuse block solve your problems? What were the symptoms?

Replacing the Main JB did solve the problem for me. The symptoms were the same as yours as I described them.

 

[Crapper49]

Replacing the Main JB did solve the problem for me. The symptoms were the same as yours as I described them.

Turns out my problem was much more mundane. My compressor was replaced with an aftermarket compressor. Turns out that the OEM to aftermarket wire connections didn't seat properly causing an occasional loss of continuity. I used some conductive compound on the connections and it's been working fine ever since (a week so far). That only took a year for me to figure out.

 

[vcheng]

Turns out my problem was much more mundane. My compressor was replaced with an aftermarket compressor. Turns out that the OEM to aftermarket wire connections didn't seat properly causing an occasional loss of continuity. I used some conductive compound on the connections and it's been working fine ever since (a week so far). That only took a year for me to figure out.

I am glad your problem was minor and was solved. A good working AC is a necessity for sure.

 

[r2550g]

thank you all very much for the write-ups! It is very helpful. Has anyone been able to find the replacement relays for those two in the original box? Thanks a lot in advance!