OK...for some weird reason, my car has a 20A fuse wired into the 20 gauge fuseable link @ the fan relay...the fuse keeps blowing all of a sudden...the fan motor is fine, and isn't shorting out, so my guess? is that it's grounding out someplace?

This is what the fuse wired in looks like..



This is how the wires are done up...I cross referenced it to the manual diagrams, and they seem right. The problem lies in port "D"...it's a red wire that goes to the "power feed" (whatever that is), and is called the "Thermo HW" (hot wire?)

Anyways, the electrical tape wrapping the red wire looked whacked, so I rewrapped it, and since then, it hasn't blown yet...but I think that's a coincidence...




As you can see, I dunno what I am doin...

Can anyone help ?

 

Stuart,

I have a '91, and I think my schematic is the same as yours.

Before going any further, I would want to know if the fuse if for the relay coil or the relay contacts?

According to my GM manual, the "D" terminal connects to the relay coil which is powered by +12 from the ingition switch via the 20 ampere FAN FUSE. The "F" terminal connects to the other side of the relay coil and is grounded to switch on the relay (fan) by whatever switch it's hooked up to. The coolant fan switch, the A/C pressure switch, or a toggle switch if someone hooked one up.

I am curious to know why you said:

On my '91, there are no 20 gauge fusible links for the fan(s). The closest to a 20 gauge wire is an 18 guage wire which is brown. This is the wire supplying +12 to the relay coil. Same color and size for both of my relays.

I don't know why GM used a 20 ampere fuse to power these two relays. This fuse also poweres the alternator "turn on" circuit located inside the regualtor, which is also an 18 gauge wire. Each relay draws ~300mA (0.3 amperes) and the alternator probably doesn't draw more than that, so I would think a 3 ampere fuse would be okay.

If this in-line fuse is protecting just the relay, a 3 ampere fuse would be enough - but then it's in the wrong location - it should be at the source of the voltage, such as at the battery if it's continuous or the ignition switch (or close by it) if it's switched. This is to protect not only the relay, but the wire powering the relay coil.

Was the connection under the electrical tape soldered, crimped or just two wires twisted together? It should be at least crimped, preferably soldered (IMO).

Nice images.