Multiple electrical gremlins - help please!

[neil30076]

:banghead:
I couldn't figure out how to delete my original thread, so I'm starting a new thread.
Everything works as designed if i start the truck, but flasher relay keeps pulsing at about 2/second.

BUT....
When i turn it off and remove key....
The flasher relay keeps pulsing, and the two electrical fans in front of the radiator are pulsing on and off, and the green trailer light is flashing very faintly and slowly. Oh, and the alarm goes off after a couple of minutes
It has been very dry here for some time, now raining like crazy, maybe water got in somewhere it should not be?

 

[singingcamel]

If you have a trailer harness may be a direct short or bad wiring ,that's where I would start. don't know what the deal is with the cooling fans but might be related, doubt it tho.

 

[discostew]

First I would make sure the inertia switch isnt tripped to its first stage causing the lights to flash. But if You already checked that I would be looking at the multi function unit. I've seen a couple of those do goofy stuff and it always seems to involve flashing lights.

 

[ezzzzzzz]

Do you have a trailer wiring converter in the back? I've heard of these failing and causing similar issues. It could be the MFU, Z148, located left of the steering column behind the fascia panel. As for the fans, do they continue to pulse on/off for hours or just a few minutes? They have nothing in common with the trailer wiring with the exception of fuse, F-1.
The MFU is the larger unit with the label showing.

 

[neil30076]

Do you have a trailer wiring converter in the back? I've heard of these failing and causing similar issues. It could be the MFU, Z148, located left of the steering column behind the fascia panel. As for the fans, do they continue to pulse on/off for hours or just a few minutes? They have nothing in common with the trailer wiring with the exception of fuse, F-1.
The MFU is the larger unit with the label showing.

Thanks, Yes, I have trailer wiring converter, i'll disable it and also see how long the fans run for.
When it stops raining here i'll hook battery back up and check. What is the part number on the MFU?

 

[discostew]

Thanks, Yes, I have trailer wiring converter, i'll disable it and also see how long the fans run for.
When it stops raining here i'll hook battery back up and check. What is the part number on the MFU?

I think its strange that your fans stay on. Don't go try to buy a MFU until you know its causing it. If it is causing this I would want to check it for water intrusion. It sits in a place that gets wet if you have a leak at the bottom of the windshield.

If you don't think you have a water leak you still could. one of the cars I had with a wet MFU had a leak into a rubber sound insulater pad and dripping right into the MFU. Windshield only leaked when the car was moving. Got pushed under the base of the windshield in the hood hinge area.I'll never forget that nightmare.

 

[discostew]

But also taking out the trailer harness would be the first thing to do. I just think the fans running kind of eliminates that. Sometimes when fans run its because the engine control module is in a diagnostic mode. Or it thinks the engine is really hot.

 

[neil30076]

I think its strange that your fans stay on. Don't go try to buy a MFU until you know its causing it. If it is causing this I would want to check it for water intrusion. It sits in a place that gets wet if you have a leak at the bottom of the windshield.

If you don't think you have a water leak you still could. one of the cars I had with a wet MFU had a leak into a rubber sound insulater pad and dripping right into the MFU. Windshield only leaked when the car was moving. Got pushed under the base of the windshield in the hood hinge area.I'll never forget that nightmare.

I think you are on the right track, i noticed a few drops of water on my left foot when i moved the truck, and they are probably coming from that area. I'll dive into in shortly and report back.
Thanks
Neil

 

[neil30076]

Update, thanks discostew.
Leak at bottom of windshield, water in base of connector 'L' on main fuse panel. Resealed windshield, dried out and cleaned pins around 'L' and all is now well. we will see what the next heavy rain brings. Haven't figured out what flows through 'L' and Rave is not much help .
Neil