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Wife put jumper cables on backwards 3 years ago, and blew a couple of fuses. I replaced the fuses and all was well except the illumination behind my climate control *****. (and also the illumination behind the blower speed *****, and headlight switch/**** and dimmer switch) All instrument cluster lights work, radio lights work, power outlets work, all switches work... dimmer control works for the radio lights and cluster lights. But I get no illumination behind these switches/***** no matter what I do.
I’ve checked every fuse in the passenger compartment fuse-panel,(#10 was blown, but replaced), and I’ve visually checked every one of the fuses in the fuse-box under the hood. All good.
This has plagued me for 3 years, and it’s high time I figure out what’s keeping it from working! I pulled the bezel off the dash, and checked the 2 bulbs behind the climate control *****. Both looked good.
the only other thought I had was if those bulbs were in series with the bulbs behind blower switches, and headlight switch illumination?!
Fuse 10 is the one that feeds those lights. Problem is, they are turned on and off by a transistor in the smart fuse box. That transistor may be blown. They are most likely using the transistor to dim the lights by the dimmer. How much is a smart junction box for your van?
I did have a fleeting thought that the fuse might be fed through a relay somewhere... but without access to the electrical prints, I just abandoned that line of thought. Lol!
do you have any idea which transistor controls fuse #10? Is it the block in this photo? The dimmer switch works for the other lights.... I did pull the block and meter it, but I have no idea what readings I should expect for good/bad. Lol
looks like I can get a used Smart Junction box for anywhere from $65 to $130... although I assume I can just replace the transistor?
im still searching to find information, but your reply certainly gives me a new direction in which to search. Thanks again!
Here's the best price on an EVTM for your year and chassis: 2011 E-Series EVTM
Grabbit and rock n roll on your electrical issues. That DOES NOT include any information for the microprocessors etc that might be inside the instrument cluster. It won't delve too deeply into a SJB either so maybe not useful for this problem.
Anyway good luck with that nagging annoying issue!
I did have a fleeting thought that the fuse might be fed through a relay somewhere... but without access to the electrical prints, I just abandoned that line of thought. Lol!
do you have any idea which transistor controls fuse #10? Is it the block in this photo? The dimmer switch works for the other lights.... I did pull the block and meter it, but I have no idea what readings I should expect for good/bad. Lol
looks like I can get a used Smart Junction box for anywhere from $65 to $130... although I assume I can just replace the transistor?
im still searching to find information, but your reply certainly gives me a new direction in which to search. Thanks again!
-Kenny
You are thinking correctly, in the old days they would have used a mechanical relay like you have circled in the above picture. Now what they do, instead of a relay they use a transistor mounted on a circuit board behind the fuse box. It's not serviceable. As you can see you still have a mechanical relay that you circled, but a lot of it now is on the circuit board in behind.
You are thinking correctly, in the old days they would have used a mechanical relay like you have circled in the above picture. Now what they do, instead of a relay they use a transistor mounted on a circuit board behind the fuse box. It's not serviceable. As you can see you still have a mechanical relay that you circled, but a lot of it now is on the circuit board in behind.
Ok, I had that box pegged as a relay until
you mentioned a transistor... lol! So you are saying that behind the fuse panel, built into the SJB, there’s a circuit board? This is why replacing the entire SJB might be a solution? That makes sense I suppose.
I’m going to go read up on this. Might get the electrical prints book suggested above too. Seems a lot hurt to solve a tiny backlighting issue... but by golly, it’s annoying me! 😅
The smart junction box is hooked into a communication network on your truck. The communication network is two wires, and it communicates with a brain in the cluster, the engine computer, the smart junction box, the ABS computer, etc. I am sure I left out something. When you turn switches up at the steering column for instance, this is communicated to the cluster computer. The cluster computer communicates this over the two wire network to the smart junction box. The smart junction box takes this information and switches the correct transistor on it's circuit board and that sends power to the light or whatever you want to turn on or off.
01-20-2021, 06:10 PM
