1987Stevo

Hey Guys,
i have an odd problem. i have a 97 f-150 and my interior lights stay on and cargo lights.

Also all my lights work fine (low high fogs turns brake lights) except when i go to put my parking lights on or my head lights. when i do that my high beam indicator comes on along with my turn signal indicators and my turns signals will not flash.

to top it all off if i open the driver side door this problem goes away if i close the door the problem comes back. when the lights are off the problem is nonexistent

I have check both grounds by the kick panels and brushed new surfaces for them. Did not help at all.

Also my blower motor for the ac/heat does not work at all i check the connectors with a meter and i get .78 volts to the connectors.

I also attached a picture of this large connector under the steering that can be the main cause of this. I cannot find where this plugs into

Any help will be great. Thanks

knightfire83

That connector / wiring harness would go to a previously installed aftermarket alarm or remote start system. Most likely an alarm.

These systems have connections to both the headlight switch circuit and the door latch switches, among many other. Apparently the two systems are misbehaving due to the previous attempt of an alarm install.

I would start by tracing back and removing that harness one wire at a time, restoring the original factory configuration. Be sure not to leave any bare wires, insulating them at the prior connections as necessary.

As far as the blower motor, the first thing to check would be all the fuses in the circuit. Next would be relays, the selector switch, resistor block, and then the wiring.

The blower motor circuit is always hot. The selector switch activates relays that ground the circuit thru various resistors giving you the multiple fan speeds. (At least on my '97.) I would bet it's a fuse, considering nothing works at all.

Hope this helps

1987Stevo

Thank you that great because i dont have the remote for the alarm system nor do i see the alarm system box any where under the dash.

so what i will do is i will just snip all the wires that spliced into other harness to remove that one and wrap them up.

as far as the blower motor. i checked all the fuses they are all good so i am guessing its the relays so i will check those out.

Any idea on where they are located?

are they by the blower motor or closer to the switch by the radio?

Thank you for the help i will keep you updated i probably wont get to it until Tuesday or so.

knightfire83

Be careful when cutting out that harness. That relay taped in there is likely part of a starter kill circuit. If so, you would have to remove the relay wiring, then reconnect the two factory wires back together so that your truck will start. It should be apparent where they spliced it in, the two cut ends should be the same color.

But back to the blower motor....

Turns out there is one relay, it is located in the blower / flasher relay block:



The circuit diagram:



The blower motor resistor can be located by following this connector / wires in the passenger foot well:


To the actual resistor located right next to the blower motor itself:


The fuses in the circuit are:
Engine Compartment- Location #23, 40 amp
Interior Compartment- Location #24, 10 amp

1987Stevo

okay so i cut out that wire harness and reconnect all orginal factory wiring back to the original wires (pink with yellow spliced back to pink yellow ect.)

No difference with the light indicators.

as for the blower motor relay i am currently working on that.

Any other ideas on what the light indicator problem would be ? that's my main priority

Thanks for all the help so far.

1987Stevo

Any have any help in this? Problem still isn't solved yet.

Tonight I am going to check the grounds in the front and see if there is any thing else spliced in but I think the splices are all out.

knightfire83

Not having access to a complete wiring diagram for the truck has complicated the troubleshooting process. It would take a long time to research every possible connection, even with a diagram , that would cause the problems you are having. The electrical system on 90's on up vehicles are pretty complex, I'm guessing this is why there hasn't been many replies.

As far as your indicator problems, I'm trying to figure out what all the symptoms have in common.

Turn signal/ parking lights and high/low beams are routed thru the multifunction switch for the turn signals, but...

The door open switch goes directly to the GEM (BCM) module. So how this would effect your problem IS the problem in troubleshooting it.

I don't know if the headlight switch goes to that module, seems it would be simpler to just have the switch control relays directly.

If your truck came with a factory alarm, I would imagine it would have all the connections to these circuits also.

They do all have one 100% commonality though- the instrument cluster. The door ajar light, turn signals, high beam indicator are all connected there. Perhaps a ground going to the cluster is bad or non existent? Maybe bad connections there.....

Since a previous owner installed an alarm, there is also other possibilities that the wiring was hacked into at other locations too, perhaps near the GEM / BCM or behind the foot well panels by the doors.

Whats the deal with the Interior and cargo lights staying on?
What is going on with the high beam indicator?

I'm probably over thinking this, I'm just throwing out ideas..... It could be something as simple as the dreaded water leaking into the GEM module problem:

https://www.f150forum.com/f6/gem-ans...-issues-43475/

cardinexile

One thing that can also cause intermittent electrical problems is the wire running from the overdrive switch. Take the steering column cover off and find where the wire comes out of the gear shift. The wire chafes on the lug on the column. My neighbor has a f250 that had a similar fault and I fixed it in about a half an hour with a few wraps of tape. The stealer ship wanted 2k to replace about half the truck. It could be one of your problems. Also check the wires coming out of the turn signal switch.

1987Stevo

Thank you I will check all of those problems.

As far as the big beams the lights them self's work correctly but the indicator is opposite. High beam indicator is on when low beams are on.

If it helps I. Noticed today that when the indicators are on I can get the blinker indicators to flicker if I mess with the blinker lever.

Like if I try to flash the blinker manually it will get like one flicker out of it each time like its about to blink but then stays soild it's extremely brief

cardinexile

Do you have led turn signal bulbs? If so, you'll need a new relay that works with LEDs. The stock one will flash very fast.
It sounds to me like your problem in located in the steering column. The switch could be bad or you've got a broken or chafed wire.