Eff10
OK. Here is what I would suggest. I'm going to let you know how this system works first. After looking at the "Fuse Block Details" diagram, it seems that your vanity mirror lights and map lights run off a busbar through a shunt on the same fuse but separate from the rest of the lights. This is an Orange 18 gauge wire coming out of the fuse block. Since they work (at least sometimes) this would isolate it to the other circuit on the HORN/DM fuse. Your lower lighter outlet runs off a completely different circuit.
Th second circuit is for the rest of the lights and it is an Orange 16 gauge wire (bigger diameter for the increased load) coming from the fuse block and it feeds a splice that all lights connect to as well as the electric mirrors (if installed) and rear window release circuit. (If you have these, do they work?)
If any one of these are shorted, it'll blow the fuse. One way to isolate it is by pulling all the bulbs and checking for short from hot to ground. Put you multi-meter on Ohms and put the red lead on the hot (usually the center of a socket) and the black to ground (the outer shell of the socket is a good one). If you get infinity (or just about zero resistance) you have a direct short. If the meter doesn't move, it's OK. Any other way you figure out that works, go for it. I personally like to isolate the individual item to make sure, but I'm a pretty **** dude.
I really would be suspect of two areas first. No. 1 would be the upper cig lighter. No. 2 would be the dimmer switch. I also think you need to fix (replace) the door jamb switches that are bad to eliminate that problem if you haven't already. They will cause you all kinds of headaches.
ohsofly & Eff10,
According to the wiring diagram for the fuse block, the 5 amp fuse you see appears to be for the instrument lamps. The fuses are labeled with nomenclature below the fuse. The LPS side is for fog light indicator light on a 2 wheel drive Blazer and the one labeled ACC is not used. Believe me, you have to have a diagram to figure this out. I had to go to about 6 different diagrams to get the scoop.
Any questions, here to help (not confuse).

 

The blower thing is a separate issue and does not work like you think it might (been there, done that too) and we'll address that later if you want. I have a few suggestions to try out but you need to have the meter. By the way, the lower "lighter" is a power outlet for a phone, etc. I guess a lighter would work in it but I have had both of mine apart and they aren't put together the same way by a long shot.

 

Well thanks, Im headed to the parts yard tomorrow and things I am going to try and get:

Door jam pins
Dimmer switch (my dimmer doesnt seem to work right, the dash lights flicker)
FPR, spider, and all that fuel system junk if I can get it
Coil and distributor shaft
center console lid
left driver door armrest
And any other small items I remember as I see them

The UpullIt here has about 10 blazers in the yard right now, hopefully I can find all the stuff I need.

 

Of you can find a good lid, good luck. Mine sure is toast. Got one coming though. I'd be a little leery of the used fuel stuff. You can get rebuilt setups for about $180.00 exchange with a warranty.

 

I want the used stuff so I can switch one part at a time until I get this thing to run.... I have no idea how to tell if I have a bad injector, or FPR, or coil...

I took the vortec cover off, and took out that black round thing and looked into the hole to see if I can see puddles of fuel, it just looks oily and I cant smell gas..

It was running fine when I got it, then started stalling so I did a major tune up, it was running OK, then it started stalling again. I had it towed home, and not it wont start. I can hear the fuel pump working. Im going ot change out these used parts and see if she will start. Then Im gong to drop the gastank and check if the flue line came off the pump (it happened on a sunbird i worked on this summer)... Im getting frustrated and need to get this truck running for her so my girlfriend stops driving my truck...

 

You can check the fuel pressure with a gauge at the schraeder valve next to the distributor. Should be about 55 - 61 psi. If you want to bypass the relaym there is a pump prime electrical connection on the right side of the firewall with the wire coming out of the junction block wiring loom. You can hook this up with a fused jumper wire direct from the battery and the pump will run continuously. The check for the FPR is to run the pump to get pressure and then slowly squeeze the return hose (about 9" long) under the truck) and the FPR should maintain pressure and not go higher than 61 psi (per troubleshooting guide in factory manual). Gonna take two people to do it unless you have a heck of a long hose. Trying to help. I've resurrected my Blazer from the dead this fall and have been into more stuff than even I can imagine. If you didn't smell gas it's probably not leaking. 60+ psi = mucho fuel. Don't blame you on the used stuff then. Just hope you don't inherit someone else's problems.

 

Gimpy: I have a rear hatch button and it doesn't work which makes sense. So once I get a tool to check the bulbs, what happens if I find a short with one of them? Also, how would I go about checking the dimmer switch or the hatch release for a short, or should I just start with the bulbs to keep it simple? I don't know if this makes a difference or not but when I found the bad fuse in the HORN/DM switch when I bought the truck, it had a 5 in it instead of a 20. Also, I don't really use the lighter I just need an outlet for my phone, but I think I'll take a trip to the store today so I can get started on this. My boyfriend just reminded me of some stuff that could be important. This truck has some extraneous wiring that used to be in use but is no longer. The rear speaker wires aren't connected, the truck used to be hooked up with a sound system in the back, there was a plow setup which left behind a red switch under the dash and a random red light above the 4x4 button. The overhead console has 2 switches on it that don't appear to do anything but proves that someone was messing around up there at some point. I can take a picture if you like. And finally, the glove box light doesn't work but the light in the ashtray does.

ohsofly:
I've never seen a console lid that worked or was in good shape. I'm so jealous if you find a nice one. Also, good luck with the fuel issue. My boyfriends blazer needed a new spider and it ran like you say yours did, plus there was fuel in the oil. We fixed it but it was not fun getting stuck on our way to the grocery store. Something to think about: My boyfriend's truck also ran just like that when the 02 sensor kicked the bucket. If you didn't see fuel washed away on one side of the plenum I'm going to guess that a spider is not your problem.

 

Eff10
What you can do if you find a short is to get a new socket to replace it or just leave the bulb out of it. That way it won't affect the other ones (unless it is in series which I think only the front dome light and rear box light are) in the circuit. Before you stop after finding one problem, test them all! That way you know you've got the whole thing fixed. The glove box light is in this circuit but the ashtray light isn't. It's part of the Instrument Lamp circuit (5 amp fuse). Don't worry about it now.
My Blazer has two overhead console reading lights in it with the switches adjacent to them. Are these the ones you're talking about?
Is any of the "extra" wiring hooked to anything? Is there power to the switches or whatever else is there? You need to know this because I would recommend you get rid of this stuff.
Why there was a 5 amp fuse in a 20 amp fuse receptacle doesn't bode well. It might mean they used the circuit for something else and disconnected the lights. Lets hope not but anything can be fixed. My Blazer is running proof of that. Everything works (now). Couldn't say that when I bought it. As for the rear window switch not working that's in the circuit too and like I said anything can be fixed. As for the dimmer, get the meter and we'll go from there. We'll deal with it as you find it. You should be pretty handy with a screwdriver and meter when you're done here.
One last question. Do you have an automotive salvage yard near you? You might (probably will) need it.

 

eff10 where in CT do you live, im in plainville, if you need a hand dismantling stuff i can lend a hand i have the same vehicle only chevy

 

Ok so I went out and bought myself a multimeter, a couple extra bulbs for the dome light, and an assortment of fuses. By the time I got home it was too dark to do anything so I'm going to start tomorrow. And yes the switches are adjacent to the console reading lights, they just looked to me like they didn't belong there but I've never dealt with an overhead console before. Are they the switches for the lights?
I'll check tomorrow if there is power to the extra wiring and switch. I'm not sure how to check the little red light because it is drilled into the dash right above the 4x4 button like I said. I'll update you tomorrow. I'll check to see if there is a salvage yard around. I'm not sure.

And drifter, I'm in Willington. I'll let you know if I need a hand but I probably have all the help I need here. Thanks so much for the offer though that's so nice of you. My boyfriend has a blazer too and so between the two of us it shouldn't be too hard.