I've got a 97 Blazer whose brake lights, tail lights,and directionals don't work. I replaced the ignition switch module and that didn't fix it. Brake lights work the first time you step on them, and after that, they're dead. All fuses are intact in the interior fuse block, but I haven't been able to find the under hood fuse block. I assume there is one. Can anyone point out where it is?
Another weird thing happening is that when you turn the engine on, the headlights come on. It's like they're wired directly into the ignition switch and you can't control them. But when you set the emergency brake, the lights turn off. I am considering replacing the turn signal/multifunction switch to see if this will do it. Also, reading past threads on this forum, I pulled up the carpet on the driver's side and found a wire, about 1/4" diameter, more like a cable. It's got red insulation on it. It goes back to the rear of the vehicle but I haven't traced it back there yet. On the front end, it goes through the firewall and up into the engine compartment and it's just cut off. It looks like someone just snipped it off with a pair of cutters. Is this my problem? And where does this cable go to under the hood?
A lot of questions, I know. Thanks for any help.

 

Well the fuse block inside the engine compartment should be on the drivers side just above the washer fluid resivior, however I am not sure what fuses/relays are in there.

Also for the automatically turning on headlights, the high beams turn on at a lowered voltage (daytime runnings lights) when the engine is running and the parking brake is released, if the lowbeams,rear taillights, and turn/park lights come on, then I would check to make sure you dont have anything covering the passenger side dash speaker as there is a daylight sensor there that automatically turns on headlights.

Not sure about the wire, never looked into that before.

As for the rear lights, I have heard that there is a plug connection of wires in the back inder the bumper or in the trunk that some people have had come unplugged, which would allow the rear lights to function properly if plugged in.

-Lenny

 

Like Lenny said, the headlights coming on with the engine and off with the parking brake is perfectly normal. If you want to over-ride this press the dome light over-ride button 4 times. You will hear a chime letting you know that the automatic lights are now off. You can use the normal switch from there.

As for the taillights, the easiest way to test if its the multifunction switch at fault is by depressing the brake and jiggleing the hazard switch side to side. If you get intermittant or any responce from doing this your multifunction is bad and needs to be replaced (most often you can get this under recall). However if yours did what mine did, its a two part deal. On mine not only did the multifunction go but my whole rear light harness from the firewall back was shot and was intermittantly working. If thats the case you got a fun afternoon pulling up carpet and panels and running a new harness or if you havean extended waranty on your truck you can have the dealer do it for free.

 

The 97 didn't have an underhood fuse block, it only has the one on the left side of the dash. The big red wire sounds like an amp power supply that was cut off of the battery by a previous owner. The DRL's are the lights that come on with the key, and again the 97 was not equipped with a dome lamp defeat switch, OR automatic headlamps, so you won't find a switch or a sensor on the right side of the dash.

 

So from lastcoupe's post, I don't have a way to turn off the daytime running lights?

The big red wire: Yes it was probably cut off by the previous owner. They did lots of butchering to this vehicle. But what is an "amp power supply?"

If I want to investigate the possibility that this is a ground problem, are there basic places to look? I know about the ground by the passenger side headlight near the windshield washer reservoir. Are there others? I thought I heard about a couple places under the dash.

Just to recap: No directionals. No brake lights (including the top rear). No tail lights. The brake lights work the very first time you step on the pedal, but after that, they're dead. All fuses intact, though I'm going to take another look.

Another thing that's happening is the temp gauge always reads the same, which is probably way cooler than the engine actually is. Oil pressure reads the same too. Both gauges never change, whether the ignition is on or off.

A little history on the Blazer (97 four door): I bought it in Puerto Rico. It had 95,000 miles on it. The previous owner had installed a stereo in it and just hacked the dash apart. Wires everywhere, spliced together. No electrical tape, no nothing. To keep the stereo in place, he used empty cigarette packs folded in half and wedged between the stereo and the dash. You're probably wondering, Why did you ever buy a car like this? It's a long story. This is a remote place and I was doing a construction job and needed a vehicle ASAP. Aside from the lights not working, it runs great.

I removed the stereo and all associated wiring, leaving only the stuff that was original to the Blazer. There are a couple of small harnesses with plastic clips on the end that are just dangling and I can't find what they connect to. They're in the area of the steering column. The clips are really small, like a quarter inch.

I did replace the ignition switch module a while back, since I got one for free and thought, why not? That didn't make a difference.

I appreciate your guys' responses, by the way.