Crazy electrical issues 1990 B II 2.9 Auto trans. manual hubs.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Joined
May 21, 2021
Messages
10
Reaction score
6
Location
Milford, MA.
All lights work, but RH Side flashes slower...?...pull headlight switch out for running lites, RHS stops flashing.....But, Wait, that's just the begining. Step on brake, works, but less volts on RHS.....L. Turn signal on, L. brake lite goes out, & back-up lites get stray voltage, like 2 or 3 volts.......R. turn signal on R. brake lite goes out [no stray voltage to back-ups ]......Pull running lites on [ key off ] step on brake, R. tail lite goes out, also the plate lites go out, & back-up lites come ON ! ......Put in reverse, [ key on ], back-up lites come on, not bright on RHS. Stray voltage in tail lites, about 2 or 3 volts....Step on brake now, L. on, R. about 6 volts...R. back-up goes out, & plate lights brighten.......Key off, step on brake L. lite bright, R. 5 or 6 volts., back-up lites 3 or 4 volts, plate lites, 3 or 4 volts... I have eliminated headlight SW. Turn indicator SW, Ignition SW, took out 4 relays, dissconnected altinator, taken every fuse out, swapped bulbs R to L. inspected wires, changed the flasher, & still have the problem ?
 
Last edited:

Tiha

Well-known member
Staff member
Moderator
Joined
Jul 22, 2020
Messages
969
Reaction score
1,010
Location
Midwest
Sounds like a bad ground. When you turn on your headlights there is not enough ground so it basically keeps the flasher on.

Could be front or rear.

I suppose could be a bad bulb too, much thinner chance of that. But I would start by pulling the turn signal bulbs and start adding back one at a time.
Does one of the marker light/turn signal assemblies seem brighter than the others with the headlights and flashers on? If so I would start there.
 
OP
OP
4
Joined
May 21, 2021
Messages
10
Reaction score
6
Location
Milford, MA.
Sounds like a bad ground. When you turn on your headlights there is not enough ground so it basically keeps the flasher on.

Could be front or rear.

I suppose could be a bad bulb too, much thinner chance of that. But I would start by pulling the turn signal bulbs and start adding back one at a time.
Does one of the marker light/turn signal assemblies seem brighter than the others with the headlights and flashers on? If so I would start there.
I do not think any od this is ground dependent, and certainly I get full voltage when the lites work properly, like on the RHS.
 

miesk5

96 Bronco 5.0
Staff member
Moderator
Joined
Oct 18, 2005
Messages
9,071
Reaction score
1,018
Location
Floating in the Pacific
Yo 4 speed,
Welcome!
As Tia advised, Troubleshooting; "...If you have a problem when turning on one circuit it causes another to come on partially (dim lights, etc.), check the ground for the part or system that was turned on first. i.e., if you press the brake pedal & the parking lights turn on partially or fully, check the brake lights' ground; This is caused by current going through brake light bulb filaments & finding a ground in the parking lt. system instead of its own ground..."
 

miesk5

96 Bronco 5.0
Staff member
Moderator
Joined
Oct 18, 2005
Messages
9,071
Reaction score
1,018
Location
Floating in the Pacific
Yo Jimmy,
Hopefully someone here can provide more ground locations and wiring diagrams for you.
Also contact your local library for possible access to on line AllData or on line Chilton.
 

Tiha

Well-known member
Staff member
Moderator
Joined
Jul 22, 2020
Messages
969
Reaction score
1,010
Location
Midwest
The grounds you cleaned go from the light sockets to the body?
Then there should be a body to frame.
Also a body to battery.
The backup lights getting stray volts really points to bad ground someplace.

If it is none of those. Then you are looking at a pinched or melted harness someplace.
 
OP
OP
4
Joined
May 21, 2021
Messages
10
Reaction score
6
Location
Milford, MA.
The back-up lites will work fine, as long as nothing else comes on. It is Not like they do not work, they do. They will get the stray volts, when the tail lites are turned on. ? Crazy things happen, like when the brake gets applied.
I have a Great ground, just that the problems are associated with the R.H.S. That has to mean something ? when the back-up lites do get
the stray volts, like 2 or 3 volts, it is BOTH ?
 

Tiha

Well-known member
Staff member
Moderator
Joined
Jul 22, 2020
Messages
969
Reaction score
1,010
Location
Midwest
We run liftgates on the back of van trailers. When the motor ground starts getting rusty or bad operating the liftgate will light up the tail lights on the trailer.

That ground voltage is looking for someplace to go, that is where you stray volts are coming from.

Here is maybe another way to help troubleshoot it.

Take a set of jumper cables. Connect from the negative on the battery to one of the ground points you just cleaned up. See what that does.
Just connect the black cable, ignore the red one.

basically you are simulating running the ground from the light directly back to the battery.

if that fixes the problem, you still have a bad ground.

If it makes no difference then a ground is not your problem.
 

johnnyreb

Well-known member
Joined
Feb 23, 2021
Messages
2,419
Reaction score
1,068
Location
West Virginia
Since the Bronco has a aluminium hogs head. It might be like my Fairlane. When I,d park it during the winter and spring I,d get ready to run it. I,d have to take the starter off and clean it really good and also the hog head. Its some you might want to check out.Since the motor is attached to the transmission. Hogs head is the bell houseing in case some people do not know what it is. Good luck.
 

MT Phil

New member
Joined
Apr 22, 2017
Messages
2
Reaction score
2
All lights work, but RH Side flashes slower...?...pull headlight switch out for running lites, RHS stops flashing.....But, Wait, that's just the begining. Step on brake, works, but less volts on RHS.....L. Turn signal on, L. brake lite goes out, & back-up lites get stray voltage, like 2 or 3 volts.......R. turn signal on R. brake lite goes out [no stray voltage to back-ups ]......Pull running lites on [ key off ] step on brake, R. tail lite goes out, also the plate lites go out, & back-up lites come ON ! ......Put in reverse, [ key on ], back-up lites come on, not bright on RHS.I Stray voltage in tail lites, about 2 or 3 volts....Step on brake now, L. on, R. about 6 volts...R. back-up goes out, & plate lights brighten.......Key off, step on brake L. lite bright, R. 5 or 6 volts., back-up lites 3 or 4 volts, plate lites, 3 or 4 volts... I have eliminated headlight SW. Turn indicator SW, Ignition SW, took out 4 relays, dissconnected altinator, taken every fuse out, swapped bulbs R to L. inspected wires, changed the flasher, & still have the problem ?
I had a similar problem, but not the exact same. I changed almost everything. It ended up being a rear light bulb that had one side of the element fell down on the other element shorted out and did all kinds of weird crap with the lights. It was on a 76 Ford PU 1157 bulb. Good Luck!
 

johnnyreb

Well-known member
Joined
Feb 23, 2021
Messages
2,419
Reaction score
1,068
Location
West Virginia
I had a similar problem, but not the exact same. I changed almost everything. It ended up being a rear light bulb that had one side of the element fell down on the other element shorted out and did all kinds of weird crap with the lights. It was on a 76 Ford PU 1157 bulb. Good Luck!
If the bulbs have a yellow end--brassppit is American made. If it is silver--it is made in CHINA AND THEY ARE JUNK. GO TO A JUNK CAR AND GET THE BULBS FROM IT.
 

johnnyreb

Well-known member
Joined
Feb 23, 2021
Messages
2,419
Reaction score
1,068
Location
West Virginia
All lights work, but RH Side flashes slower...?...pull headlight switch out for running lites, RHS stops flashing.....But, Wait, that's just the begining. Step on brake, works, but less volts on RHS.....L. Turn signal on, L. brake lite goes out, & back-up lites get stray voltage, like 2 or 3 volts.......R. turn signal on R. brake lite goes out [no stray voltage to back-ups ]......Pull running lites on [ key off ] step on brake, R. tail lite goes out, also the plate lites go out, & back-up lites come ON ! ......Put in reverse, [ key on ], back-up lites come on, not bright on RHS. Stray voltage in tail lites, about 2 or 3 volts....Step on brake now, L. on, R. about 6 volts...R. back-up goes out, & plate lights brighten.......Key off, step on brake L. lite bright, R. 5 or 6 volts., back-up lites 3 or 4 volts, plate lites, 3 or 4 volts... I have eliminated headlight SW. Turn indicator SW, Ignition SW, took out 4 relays, dissconnected altinator, taken every fuse out, swapped bulbs R to L. inspected wires, changed the flasher, & still have the problem ?
I done alot of the too. Then I ran one wire for my back up lights-----to the switch on the transmission. The a hot wire off the switch--whit the switch in the start position. --Follow the wire OFF of the transmission .Up the firewall . It will come up about the center of the fire wall.It will have a plug. Un hook it and run you NEW wires to it. I,ll see if I can find some pictures
 

Members online

No members online now.

Latest posts

Forum statistics

Threads
22,509
Messages
135,880
Members
25,108
Latest member
Utahstroke
Top