Fuse Block Relay Problem

[jeffwalt]

Update. K1+ coil, pin #8, had no voltage with ignition on or off. The chassis battery terminal powering the board had full 12v. I'm not an electronic expert by any means but it seems I need to go upstream and find why K1 pin 8 is dead. I hope it's a simple inline fuse or maybe a related plug fell out.

[Argosy]

Check continuity from the connector at the ignition switch to the plug on the cable.

Hopefully the board is relatively close to the ignition switch so there's not a lot of looms to chase the wire. If that's not the case I'd hook the 12v to the coil to make sure the relay is good then run a wire from the IGN terminal of the switch to the coil terminal, add a fuse if you want.

[jeffwalt]

Originally Posted by Argosy

Check continuity from the connector at the ignition switch to the plug on the cable.

Hopefully the board is relatively close to the ignition switch so there's not a lot of looms to chase the wire. If that's not the case I'd hook the 12v to the coil to make sure the relay is good then run a wire from the IGN terminal of the switch to the coil terminal, add a fuse if you want.

Since the K1 relay is soldered in, does the cover come off so I can check/see what it's doing in there?

[Skip426]

Jeff , upstream from the k1 coil+ terminal ( multiple connector ) is the ignition switch , that wire is to activate the relay , no power to that wire means the board and relay are probably fine .

It's the place where Thor attached to Freightliner's wiring from the ignition switch , you need to track down , and repair.

If you're on the road you should be able to jump power to the K1 coil + wire and have the relay activate as a temporary repair . Just be sure to disconnect with the key off , or you'll drain the chassis battery.

[Argosy]

Originally Posted by jeffwalt

Since the K1 relay is soldered in, does the cover come off so I can check/see what it's doing in there?

No, they're glued together. You should be able to hear the solenoid and feel it actuate by touching the cover.

[jeffwalt]

OK, bare with me here. I checked everything again today, K1 relay is still NFG, I gave it a couple taps, no clicks, no light, no nothing. No voltage at pin8 or any other pins in that harness plug. I also checked ignition K2 relay J5 pin4, all good 12volts there.

Back to K1 pin8. It shows as a brown wire in the plug.

I checked the ignition switch through my cup holder hole. Only has red, blue, green and yellow wires. The switch looks tilted a little. I'll kill chassis batteries and reseat that.

Sooo... The brown K1 pin8 wire leaves the fuse board plug, goes upstream in the wire loom and attaches to the Freightliner wiring somewhere. Then it switches colors from brown to Freightliner red, blue, green or yellow and goes to the ignition switch.

And finally, I need to trace the brown wire to the colored wires transition point and or do a continuity check between K1 pin8 and wherever it terminates at the ignition switch. Obviously checking for problems or wire separation, corrosion, loose connectors, etc. Thanks again, I am learning...

[Skip426]

Jeff , that multiple connector ( on the ignition switch ) is not properly seated ; I'd say pull it off and check for damage on the terminals , and re-connect ; it should be seated square , not at an angle like in the picture .

[jeffwalt]

Originally Posted by Skip426

Jeff , that multiple connector ( on the ignition switch ) is not properly seated ; I'd say pull it off and check for damage on the terminals , and re-connect ; it should be seated square , not at an angle like in the picture .

Yeah, that's what I thought too, doesn't look right. We're going to Sturgis tomorrow for a week at least so I'll have more time to mess with everything while I'm safely parked. Thanks.

[jeffwalt]

Originally Posted by Skip426

Jeff , that multiple connector ( on the ignition switch ) is not properly seated ; I'd say pull it off and check for damage on the terminals , and re-connect ; it should be seated square , not at an angle like in the picture .

Overdue minor update. Took a breather for a few days plus the toilet broke and I had a hell of a time getting the ROKU hooked up to the telescoping TV.

I pulled the ignition switch connector off and it looked good. Wires in tight, no corrosion. Put back on, re-seated correctly. But, no change, no voltage at J4 pin8.

Called Freightliner and didn't get much helpful info. They did send me a vehicle interface schematic but I don't know what the hell I'm looking at.

Called Thor. Again, not too helpful. They did say the control boards are made by KIB and are currently out of stock. Available in approximately 4 weeks.

So, I think I can get a multi meter probe angled in behind the ignition switch to check the wire voltage there. I'm hoping at least the red one is from the battery. Then, I'll check continuity, and if I get brave do a jumper.

[Skip426]

Thor may have tapped into the Freightliner wiring near the chassis fuse boxes , that would be another spot to look for the power source for the relay activation wire.

[jeffwalt]

Thanks for the info. I've chickened out in my further troubleshooting quest. My rig goes to the Freightliner shop here in South Dakota on Friday.

I'll post again if resolution is found.

[jeffwalt]

FIXED! The technician at Freightliner tracked down the problem and the dash air, windshield fans, mirror adjusters, etc., are all working normal. The wife is happy.

There is a plug connector down the wire loom below the ignition switch. The tech said the body builders wires were too short and loose in the plug. As he manipulated the connector, things started to work. He refitted and re-seated the wires and restored good power to K1 accessory relay. He also tie wrapped the connector together (center of photo).

Thanks for all the help and advice on this issue. We were on the right track and I learned some good stuff.

[Skip426]

Jeff thanks for wrapping up your post , sorry we weren't able to save you a trip to the shop.
Hope the info you were able to give the tech saved some time and $$.

[jeffwalt]

You guys were more than helpful. I did relay some info to the tech, which probably helped his troubleshooting. However, it wasn't reflected in the bottom line when I paid the bill ($$$$$).

But hey, we're cool!