Dash lights flash with turn signal, brakes, windows, etc.... (1 Viewer)

Joined
Feb 5, 2010
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326
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Lafayette, IN
New to me 94 FZJ80. Been having a kind of strange intermitant problem with the electrical. I was kind of concerned driving the truck 800 miles home after buying it knowing there was some kind of electrical gremlin, but we made it with no issues. Basically, when I turn on the turn signal, I get the Christmas Tree effect.......Like it would do if the alt was going bad (Battery, brake, AT/P). But weird thing is that the lights don't stay on. They are not constant. Probably around 75% of the time (but not always), they light up when the turn signal is on, and flash with the signal.....They also sometimes(maybe 40% of the time) come on when I hit the brakes for maybe the first 2-3 seconds, then go off, even if I keep the brakes applied, they also come on (100% of the time) when I raise or lower the windows and stay on the entire time I am raising/lowering them and will stay on as long as one of the window buttons are being pushed. I have done a lot of searching, but it looks like most peoples Christmas tree effect is constant, it comes on and stays on, indicating a bad alt. Well, I have a feeling thats not the case, because as I've dug into the searches, I actually found a post from not the previous owner, but the one before him that the issue has been happening since around jan 09. See post..... https://forum.ih8mud.com/80-series-tech/266786-weird-flashing-dash-lights.html That owner supposedly eventually replaced the alt according to his post when he sold the truck and the PO, but I have no reciepts or paperwork to confirm that. But even if he didn't I would think the alt would have died by now if it was going bad then.....that has been probably 12-15k miles ago. The guy who sold the truck to me said it had been like that since he got it, and just never dug into (if it ain't broke, don't fix it, lol). But I want to get it resolved. Its obviously got to be something thats not right. Plus, it kind of freaks people out when they are in my truck and all the lights start flashing :D So, besides the standard check all the alt connections, does anyone have any suggestions. I'm just a newb with this LC, and honestly, dealing with electrical issues are not my specialty. I don't have a FSM yet, but I'm working on it. BTW - truck starts fine everyday, battery seems to be strong, nothing out of the ordinary electrically except for the Christmas tree lights. Just wanted to see if someone else might of had a similar problem and can help point me in the right direction. First things first though, I'll run by Autozone tommorow and have them run a check on the battery and alt just in case. I'll post up how that goes. Any other suggestions are appreciated! :cheers:
 
Joined
Feb 5, 2010
Messages
326
Location
Lafayette, IN
Ok, digging into the PO searches some more, I came across this post. Could this "fix" possibly be the culprit? Seems like it was doing it well before he did this though, so I dunno. He also mentions no tensioner on the alt....maybe a belt slipping? Sorry if this dosen't make any sense, i'm not too familair with alternators, but from the look of things, me and the alternator might be getting intimate here soon.

https://forum.ih8mud.com/80-series-tech/282829-snapped-alt-stud.html
 
Joined
Mar 17, 2007
Messages
55
Location
St. Charles, Missouri
Grounding issue?

I've run into similar situations in the past with cars and motorcycles, and it always seems to be a bad ground. I would inspect and clean all connections to ground, starting with the battery to engine block connection.

After that, check the turn signals and their wiring at the corners. If the vehicle had been wrecked at some point, most likely the turn signals would have been rewired and maybe not quite right.

You'll want a good metal to metal contact area. Sometimes in body repair, a ground point will get painted. It may work fine until a little corrosion builds up and then the ground fails.

Hope this helps.
-jim
 
Joined
Sep 6, 2004
Messages
2,548
Location
Hayward, Ca.
I am having the same problem on my '93. Sometimes the lights stay on and sometimes they flash. I am convinced it is not my alternator. Never any problems at all with the charging system. I am starting to think it is a bad ground of some sort. I went out wheelin 2 weeks ago and got the whole engine bay covered in mud ( I hate mud!). Maybe a ground connection got covered in mud? Or maybe my problem is in the dash/instrument panel as I was already having issues with my speedo not working (and no it is not the speed sensor in my transfer case). I am going to tear into my dash this weekend.
 
Joined
Feb 18, 2009
Messages
4
I am having the same problem on my '93. Sometimes the lights stay on and sometimes they flash. I am convinced it is not my alternator. Never any problems at all with the charging system. I am starting to think it is a bad ground of some sort. I went out wheelin 2 weeks ago and got the whole engine bay covered in mud ( I hate mud!). Maybe a ground connection got covered in mud? Or maybe my problem is in the dash/instrument panel as I was already having issues with my speedo not working (and no it is not the speed sensor in my transfer case). I am going to tear into my dash this weekend.
I have the same issue with my 93 FJ-80. I've replace headlight switch but it didn't resolve the issue. I have found out that the connector under the steering collum was loose contact. The junction looked and snapped together perfect, but when u touched the wire all the lights are flickering. So I just use the ties to tie it tight so the wire won't get loose or jiggering around.
 

kz195688

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Joined
Jun 1, 2006
Messages
253
Location
Northern VA
Bought a 94 and had the same problem. I found the nut that held the wire/s attach to the post/stud on the alternator was somewhat loose. I snugged down the nut on the post/stud and that took care of the dash lights which had been flashing. No problems for over one year +.
 

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