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73 k5 underhood fuses

blaznjon

blaznjon

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haven`t been hanging out here much lately.I got rid of my 76 and 88 k5`s lately.i decided to put my 73 back on the road .swapped the motor out of my white blazer.did the ford seloniod and ran a new wire for hei.

what do the inline 4amp fuses under the hood go to ? I`m doing a little bit of rewiring after having the 73 sit for 12 years or so.the rat must like eating wires.:eek1:

all the fuses were good I`m just curious about the fuses,and don`t feel like digging my wiring manual out. Thanks
 
I can't recall ever seeing any under the hood. Are you talking about fusable links? how about a pic?
 
I was going through old pics to try and find some underhood fuses on mine too. Not seein them and I don't remember them. I rewired mine too
 
the only fuse under the hood on my 1974 is to the AC/Heater box...that's it...no other ones
 
There r at least 2 on my 74, built in to the factory harness near the firewall. 1 towards the pass side and 1 on drivers side from memory.
Would have to look them up in diagrams. They look like round long connectors.
 
Blazer 74 thats them one right between the master cylinder and junction block,one by the ac box. i think its a 73-75 only deal since my 76 didn`t have them.I guess it time to dig my wiring diagram out.
 
mine only has the fuse near the AC/Heater box and the thing over by the master cylinder is just a weatherproof connector with no fuse in it....you push them together and it seals the connection....my original oem harness didn't have a fuse there and neither does my new oem harness....wonder what is fused there? :dunno:
 
JDNobodi said:
I believe those fuses goes to the amp gauge.
Click to expand...

That brings up a question....I changed out the instrument bucket and everything was the same except the original had an amp gauge and the replacement has a Volt gauge....
the pins on the original are at "9 and 3" position and the Volt gauge is at "12 and 3" position....

is the feed any different to either of those gauges?

could I just solder a wire from the "12 position" to the "9 position" and just use my old amp gauge?
 
I tried soldering on the circuit board. I had cut mine in half when added aftermarket gauges and I need to reconnect the ground. It work for a while till the turn signals started acting weird.

Why did you change your whole bucket? I know the early gauge stuff is getting hard to find new.
 
JDNobodi said:
I tried soldering on the circuit board. I had cut mine in half when added aftermarket gauges and I need to reconnect the ground. It work for a while till the turn signals started acting weird.

Why did you change your whole bucket? I know the early gauge stuff is getting hard to find new.
Click to expand...

I changed it because I found one in the junkyard and I had already cleaned it up and painted it...and I had shorted out the new laminate that I had got from LMC
everything is the same except that one gauge...
dang I hate to pay $80 for another laminated circuit....
 
Chief, without seeing the schematic, and right in the middle of going to bed, let me just make this point.
Ammeters and Voltmeters are not interchangeable.
Best case, it won't work, worst case it will fry something.

I doubt you are about to hook anything up tonight, but I wanted to toss that in just in case.

I can elaborate from the office tomorrow.
 
Like Fordum said don't interchange volt/amp. Amp gauge uses
A shunt if I recall. U willlll smoke it.
 
Only GM trucks I've owned that had any fuses under the hood were the first generation 67-72 trucks,they had a fuse located on each front corner above the headlamps,that were encased in a rubber holder like the plug on your license plate lamp had that pops apart--I discovered them on my 72 K5 after seeing them shown on a wiring diagram,and after I found both glass fuses were badly corroded and blown,I replaced them after cleaning the gangrene out of the holders and my long dead amp gauge started to work....:D...........................................................................................A voltmeter needs a 12V postive and ground source,an amp-meter is placed in series in between a positive power lead and isn't grounded,so no,you cant just swap the wires from an amp meter to a voltmeter....
 
Ok, got a few minutes now.

A voltmeter is basically an open circuit. It has extremely high resistance. In some of my meters its on the order of 10 million ohms per volt.
It can be put in a circuit pretty much anywhere. It measures the difference between two voltage levels.
Usually its put between the positive lead and ground.

An ammeter is real close to dead short. There is actually a voltmeter involved. But there is a shunt in the circuit. The shunt is a calibrated short. It has resistance, but it is very low, so that it only drops a tiny amount of voltage per amp.

The ammeter is a voltmeter across that shunt that measures that tiny voltage drop.

In old style trucks, all the power in the vehicle went through the ammeter. Except for the starter.
The main power feed came from the battery, up to the dash, through the ammeter and then on to the truck.
The ammeter had a copper or brass busbar inside from one leg to the other and the meter measured the voltage drop across that.

Modern trucks have the shunt in the engine compartment somewhere. Often its just a measured section of the main power lead.
The voltage that the ammeter sees is very small. Its on the order of 1/1000s of a volt per amp.
So, if your ammeter is showing 10 amps, its seeing 1/100 of a volt.

Thus, if you hooked a remote reading ammeter, like the one in your truck directly across the power lead with no shunt, its going to smoke it.
If yours was a direct reading ammeter with the built in shunt, then you are shorting the power lead to ground, which will smoke the power lead or a fuse.

If you want to reuse the ammeter, you will need the original shunt from the harness. Like I say, its probably just a measured section of the main power lead with two smaller wires crimped to it a certain distance apart.
Those two lead would go to the ammeter.

If you switch to the voltmeter, it can be in the circuit anywhere as long as it measures the main power voltage.
 
The ammeter goes through the laminated circuit so I am not sure where the actual shunt is....

I just ordered another laminated circuit and will go back to the old bucket with the original gauge...

right now the meter isn't getting any power as far as I can tell and the windshield wiper motor is not working either....no juice to those plugs as best I can tell...
 
Back to the original ?, both those 4A fuses are for the ampmeter. The one
on the passenger side connects to the firewall juction block and ties into the alternator output and is a black/white wire # 106. Not sure where the shunt is.(will look further) The other on the drivers side goes to the battery side of the starter, black wire #105. Both wires are positve to ampmeter thru the shunt. My ammeter doen't work either and has me thinking about it.
I have the factory prints but didn't see the shunt spice with a quick look.

Chief wy would you want to put a voltmeter in there with a nice original truck like yours? It could be done with some wire changes leading to the later cluster. Would need +/- and no shunt for voltmeter vs +/+ and shunt for ampmeter. Clusters do come around on ebay now and then Was just one for 73-75 recently, was going to buy it but forgot.
I doubt your inop wipers are related.
 
I've already ordered the laminated circuit so the original bucket and original ammeter is going back in there...to be honest, I don't know if the ammeter ever worked anyway...but the junkyard bucket I got must be a 1975 and the printed circuit is just slightly different and had the voltmeter instead of the ammeter...

not a biggie...bucket just has to come back out one more time (this has to be the 50th since I got the truck)

on the wiper motor....I am sure there is no power getting to it....

but once again...I don't know if the wipers ever worked...I never turned them on before I tore the Blazer down...
 
Mines been out a few time too. Just a matter of time and cash to get all working.
 
Duh!!! I never looked in the fuse holders....there are no fuses in there :doah:

Does anybody know what fuse goes in these?


DSC_00010001-46.jpg


DSC_00020002-39.jpg
 
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