Electrical issues. Looking for ideas

My wife has a 98 Ranger. For a couple of weeks, when she would turn the left turn signal on, there would be a buzzing noise coming from under the dash, and no turn signal. She would jiggle the steering wheel and it would work right. Well, about a week ago, when she got to work, she pressed on the brake peddle, and the engine died. It took a few tries to get it started again. She had to open the door, and the door ajar light and the dome light started flickering, and there was a relay behind the glove box that was clicking with the lights.

Toady, I went to get the truck from her work, and had these observations. The door ajar/domelight/relay, seemed to be something to do with the passengers door. I opened and closed it a few times and it finally stopped. When I would press the brake, the engine would die. I disconnected the vacuum line to the brake booster, and had her press the brake and it still died. I disconnected the brake light connector on the front of the master cylinder, and it still would die when pressing the brake I discovered the AC compressor was on, that is another story for later, so I turned it off and then when the brakes are pressed it just runs rough.) Also, when the headlights are on, the engine runs really rough (it seems like the PCM is not even working at all.) It won't rev, and eventually will die. OK, there's more. Left turn signal still buzzes not turn signal, right turn signal on and the turn signal lights, but both the red turn signal light and the amber marker light on the right rear blink brightly. It was then, that I noticed that as long and the truck is on, both the amber marker lights on the back are on dimly.

I opened up the dash and the steering column, and there was nothing obvious, except, there is a violet or lavender colored plastic piece with a wire to it that rides on the outside of the ignition switch, that when it is grounded, a chime goes off, like the key in the ignition. I disconnected the turn signal/hazard switch assy., but the marker lights were still on. I reconnected it, and it seemed like it was running better, without running rough with the lights/brakes, so I decided to try to get it home, where I could work on it better. We got it home, but it would not accelerate when the lights were on (it was at night,) and would start to die, so I would have to turn the lights off, and it would run fine.

So, that is where I am right now. Sorry this is so long. I would appreciate any help anyone could provide. I am not a Ford guy, so I know next to nothing about them and their quirks... Thanks again.

start looking for burned wires..... particularly around fusible links. While you are at it look for any grounds that may need to be cleaned up. The electrical systems on these are heavily dependent on proper voltage so weak batteries and dirty grounds cause problems. I had a similar issue with my Continental (may it RIP) and it was a weak charge on the battery.... seriously, it got driven like 6 miles a week and once the battery was nearly dead it did some really weird things.

anyways thats a start. the easy fix is 5 gallons of gas and a match.

Thanks bdab. I'll keep an eye out.

Sent from my ZTE V967S using Tapatalk

those are all functions of the GEM or body control module or what ever Ford called it that year..... that would also be a device of interest.....

texashale said:

................., so I decided to try to get it home, where I could work on it better. We got it home, but it would not accelerate when the lights were on (it was at night,) and would start to die, so I would have to turn the lights off, and it would run fine.

So, that is where I am right now. Sorry this is so long. I would appreciate any help anyone could provide. I am not a Ford guy, so I know next to nothing about them and their quirks... Thanks again.

Click to expand...

Reads like the first issue to address would be the alternator.
Engine stumbling with head lights on and then running better with lights off means the alternator is not adding voltage to the system, you were/are running engine on battery power and it was getting low.

Volt meter set for DC
Key off
battery voltage should be 12.4v or higher
Engine idling
battery voltage should be 13.5v or higher

If battery voltage is the same engine off and idling then alternator is not being turned on or voltage regulator in the alternator is bad.
A running alternator's minimum voltage should be 1 volt above batteries voltage, 2 volts just after starting to recharge battery, this is not a Ford thing, all alternator systems work this way.

Alternator is turned on when key is turned on, this circuit runs thru the Volt gauge in dash or the battery light, whichever you have.

If you do have a short or bad wire under the dash then it could be preventing the alternator from being turned on.
Or the low voltage of the now drained battery could be causing most of the problems.

RonD, I was thinking about the alternator.however, that battery has a good charge, it starts the truck very well. Lights are nice a bright. But I will look at it anyhow. Thank you.

BDAB Do you happen to know where the BCM would be on this thing? Or at least a general area?

got no idea. the location for the bcm is different between a Ford Ranger and a Lincoln Continental or and F-150...... I'm not even sure its called a Body Control Module and not a GEM.

GEM is left of center dash, behind the radio surround panel.
Remove the two screws, underside. The rest are friction clips, pry it out straight out.

Clean up your grounds under the hood. All the GEM functions apply a ground.
Grounds are located:
Front inner fenders (3)
B- to frame to block
Radiator support
Head to Wiper motor bolt

Earl43P thanks, I'll take a look. When I think about it, I realize that t all of this started after I had a new radio put in there. Is there something they could have done to screw up the GEM?

Sent from my ZTE V967S using Tapatalk

update

I have not checked the grounds under the hood, but have another question. First off, the front hazard lights work, but not the rear. So I am thinking it is an issues with something going to the back of the truck. Incidentally, it is a 96, not a 98, as I previously mentioned (don't know if that matters.) I found the GEM and reseated the connector. Also, I discovered a curiosity. The door ajar switch and the hazard lights seem to go through the same relay under the glove box. Is that the way it is supposed to be? For the door switch, what is the best way to deal with it? I have seen people say to spray WD40 into the latch, or open the door and spray WD40 into the latch that way. Or should I just get a new switch, and how hard is it to get to, to replace? Thanks guys, Mike