I have a 95 blazer, and I keep blowing the #4 fuse as soon as I turn the key to ON!!! Is there anyway a relay could cause this by being stuck open or closed? And does anyone know exactly how many relays a 95 blazer has and where are they all located???

 

relay is unlikely. You have a short to ground somewhere after the fuse.

 

What is the #4 fuse used for?

 

Fues 4 is for the control module and instrument cluster.

 

By control module do you mean body control module?

Anyways shlprock, suggest pulling the door switches out and checking the wiring. With the door switches pulled, check voltage across #4 fuse terminals. If 12V, then the short is still present. If 0V, then it is related to one of the door switches.

You could also pull the instrument cluster out since it is farily easy to do, and again check the voltage across #4 fuse terminals to determine if there is a short in the instrument cluster.

Anyways, couple of thoughts.

 

When you say pull the door switches, do you mean the connectors or the whole switch? Same for the instrument cluster?? Also, what do you mean by door switches, are you talking about the switches that control the locks and power windows, or the buttons that tell you when the door is open and lets the over head lights com on??? When I check voltage across the #4 fuse terminals, is that with key ON or OFF?? What's the best way to get to the door switches and instrument cluster?
Also, I pulled the negative cable off the battery and cliped a test light to it, and then touched the light to the negative side of the battery! The light came on and then slowly faded out!! ( it took just a few seconds to fade out) I know if the light comes on it means there's a short, but I thought the light would stay on and not fade out! Does anyone know why it would fade out???

Thanks for everyones help, wiring problems can be a nightmare!!!

 

These are the components connected to the #4 fuse!!

In the manual, it's labled GAUGES!

Alternator Field, VTC, A/C Compressor Relay, Cluster
Chime Module, DRL Relay Coil, Four-wheel Drive
Indictor Lamp, DRL Module, Rear Defog Timer, TCCM
Ignition, SIR Redundant Ignition, RKE Ignition

 

Door switches are the ones in the jambs that turns the dome lite on when door is open. Just pull the switch out of the dash so you can get to the wires/connectors. The idea here is to move these wires and see if the short on #4 fuse continues or not.

But according to the list you made, the door switches are not on this circuit, so probably forget about them. Does not look like the instrument cluster is either.

The test lite shows if current is flowing; appears that current flowed and then shut off or at least went to such a low value the test lite would not show.

Tells me that the short is not a "hard" short. So, try putting the test lite across #4 fuse and see if it does the samething. Will need to put the key in ON position with the battery terminals connected.

If the test lite does the same, then time to start disconnecting items on the list above to determine which is causing the intial current draw.

 

You haven't replaced the heater core lately have you?
I know this sounds weird but when I replaced the heater core and had the dash apart, when put back together I pinched the wire for the dash and was blowing fuses. Had to go back in and fix the wire.

 

First off, I havn't changed anything, it just blew one day while I was driving! The gauges must be on this fuse, because they all went dead when the fuse blew! Do the switches on the door jam just pop out from the front? Is it posible that it's a bad capacitor, and thats why the light slowly goes out??? How about the ignition itself???