I have to investigate the wiring to my new electric fan more thoroughly -- something isn't right!

Everything works okay, but yesterday I was adjusting my electric choke on the carb and so the truck was in park, idling for a few minutes ... next thing I know, my anti-freeze is starting to boil over! I run and look at my temp gauge; it's way UP! I look at the fan; it isn't running! I shut off the engine (stupid, I guess) and anti-freeze starts boiling! In a cloud of white smoke, I'm replacing the 30 amp fuse between the battery and fan relay.

I started the truck back up and took a spin ... she cooled right down and all was fine ... but WHAT made the fuse blow during idle???

Something isn't wired right ... I think it's the alternator -- 10-gauge power feed comes from the EZ-Wire fuse box under the dash -- am I on track?

I've got an 8-gauge feed from the battery + to a 30 amp in-line fuse ... that goes to the relay for the electric fan.

Main power for the fuse box (under dash) comes from the starter.

I'm gonna do the MadElectrical deal, where I can run an 8-gauge wire from the battery + to a junction box on the firewall and feed the alternator, the fuse box (under dash) and the electric fan relay. Do you think this will help?

Thanks!

Alan
54 Chevy Pickup

Are you saying the alternator feeds the dash?
I thought the alternator should be hooked straight to the battery.
I use the MAD terminal blocks, one on one side of the engine bay
which also feeds one on the other side.To the second I have wired my dual fans and headlight relays.
Do not use bladed type plug in fuses with your fan relays,
use fusible link wire.
When you phone MAD to order the terminal, tell him the problem you got, he is more than willing to help.
Start here http://www.madelectrical.com/newstuff/
you can go straight to the terminal leaving out the horn relay.
BTW read the section on Electric Radiator Fan Systems here,
http://www.madelectrical.com/catalog/rly-1.shtml
Good Luck.

Hey, Malc

I believe the EZ-Wire kit takes the battery + feed to the fuse box via the starter ... then from the fuse box runs a wire to the alternator ... or something like that. In any case, they are running a very long 10 gauge wire from the battery feed to the alternator and I want to modify that using the terminal block from Mad Electrical.

I'm gonna do the same thing you've done -- 2 terminal blocks, one on each side of the firewall. I'm gonna run an 8 gauge wire from the battery + to the first terminal, another 8 gauge wire from the first terminal to the second. Then I'm gonna kill the starter (batt +) feed to my fuse box and feed the fuse box from one of the terminals; feed the alternator and the fan from the terminals, and apply his double relay deal to the fan. I'm also gonna install relays for my headlights.

The fan was originally setup with a 30 amp circuit breaker -- I didn't want to use a fusible link because it's a lot harder to replace ... so when I got rid of the faulty circuit breaker (see my other post), the auto store didn't have any 30 amp circuit breakers, so I bought a 30 amp in-line fuse instead.

I've read those articles, Malc - thanks.

In fact, after reading this note at Mad Electrical, I'm thinking the whole problem here is the in-line fuse I installed -- so I replaced it with an 18 gauge fusible link (that's just an 18 gauge piece of wire, right?):

The same type of “Thermal Runaway” problem is also likely to cause failure of the ordinary “cartridge type” in-line fuse holders—It’s why we have supplied the 18gauge Fusible Link in our Relay kit.

Alan
54 Chevy Pickup

Alan,
Check your ground connections too. If you have a marginal wire connection it will cause the circuit to draw more power.

The startup current is what is probably giving you fits. The initial current surge to the fan may be above what your fuse can handle. The fan may operate at 15 amps but it's startup may be 40! After a while the fusible material will fatigue and fail. Is the fuse blown to where the case is discolored, or is it just opened up. That will tell you if it's a big short or just a slight over current.

Regards
Mark

This is a fusible link out of a MAD relay kit, I don´t think it´s regular wire.This is "softer".

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Mark -- Thanks, bro'. The ground connection for the fan may not be the best, now that you mention it. It's just a ring-teminal bolted to the inner fender ... would the frame be a better spot?

You're right about the startup current -- those fans KICK in, big time! Mad Electrical says those 30 amp in-line fuses *will* cause problems, so that *was* the problem I experienced, and for just the reason you mentioned. The case of the fuse *was* discolored.

Malc -- Shoot. I've just got a 6" piece of 18 gauge wire in there now and no fusible links around ... I hope I don't kill myself!

I'll be calling Mad Electrical first thing Monday morning and ordering a bunch of stuff ... I'll get it shipped ASAP and by this time next weekend, I'll be solid to go -- if I don't burst into flames before then.

Alan
54 Chevy Pickup

While your checking, do the battery to chassis and motor to chassis grounds.

I just went out and gave the electric fan ground wire the once-over. I disconnected it, wire-brushed the connector and cleaned off the spot where it connects to the body -- I think I exposed more bare metal than there was, plus I put some di-electric grease on it and cranked it back down good and tight, so I know I've got a better ground connection than there was.

I'll check the bat and chassis grounds when I go out again, but those are new 1 gauge cables, recently installed, so they should be fine.

I'll be going to my Mom's in a couple of hours foe Easter dinner ... we'll see if things look any better.

Thanks guys -- it sure helps having a couple more heads when things get like this, doesn't it?


Alan
54 Chevy Pickup

Hey Alan,
Out of curiosity how far is your battery from the fan? Maybe run a ground wire from the battery to the fan instead. Or from your current spot to the frame as well. Remember the only thing actually making the ground on the body is all the bolts, rust and stuff makes for a bad ground. I Glad I was finally able to GIVE some helpful advice this time instead of always asking.

Regards
Mark

BTW Happy Easter everyone

Well, I just got back from Mom's ... everything seems to be just fine. If I'm driving (1000 rpm or more) and the fan comes on, the voltage gauge doesn't react at all; if I'm sitting at a red light (600 rpm or so) and the fan comes on, the voltage will drop from 14 to 13 volts for a second, then comes back up to 14.

No problems. I think it was my a mistake, as Malc pointed out, to use a bladed type plug-in fuse!

My battery is located 3.5 to 4 feet away from the fan ... I've got a 1 gauge wire from the battery neg. post to the engine block and coupled there, I have a flat braided ground strap that goes to the frame. The connection at the engine block is only 2.5 to 3 feet from the fan.

I guess it wouldn't hurt to run the fan's ground wire to the engine block, eh? 3 feet ain't too far and that's a power-ground!

Alan
54 Chevy Pickup

Alan, there is a bunch of info in the Madd Electrical link. There is a chart in the one wire vice 2/3 wire alternator section that tells you what size wire to use between the alternator and battery terminal for a given distance. You may want to review this to ensure you are using large enough wire. In my case with the battery in the trunk of my coupe and under the seat in the pickup, I am using a # 2 wire. I also have a ground from the battery to the starter bolt and from the starter bolt to the frame and from the frame to the cab/body. I use a 40 amp relay for the fan and it is protected by a 30 amp fuse in my control panel. I also "cooked" a quick disconnect blade coupler on the fan ground wire early on. Those fans draw the current and the better the ground and fewer connections you have, the more trouble free the system, as has been stated by other posters.

By the way, I use Optima batteries because they are inside with me and there are no fumes. Also, they have both side and top terminals. I hook my control panel directly to the top posts, both positive and grond and the starter post and ground to the side posts. My Alternator lead goes to the starter post also. Every circuit on my vehicles are run through the control panel. I personally do not like fused links and in line fuses and that is the main reason I pay the extra bucks for Ron Francis Wire Works control panels!!!

Don´t use di-electric grease MAD advises cleaning the area to shiny metal and applying oil, the bigger contact area the better.

Trees -- I checked and double-checked at Mad Electrical ... but I can't find the chart you're talking about:
One Wire vs Three Wire

PS -- When I said my batt ground is wired to the "engine block" I should have said the "starter bolt." However, I need to add a wire from the frame to the cab/body.

Question #1: When you say "control panel," you mean your main fuse box - right?

Question #2: Why the "Quick Disconnect Blade Coupler" ?

I also have an Optima battery in my truck (thanks to talking with you about it last year) -- there's the typical door/access under the floor on the passenger side of my truck.

I don't care for the idea of fusible links, either ... too much work when one blows, compared to having a circuit breaker or fuse ... however, I've developed a sincere respect for the guy at Mad Electrical, and he uses a fusible link on electric radiator fans -- THAT, combined with the power surges that STOPPED when I bypassed the 30 amp circuit breaker on my fan, has me wondering. I'll be phoning him today and talking to him about all this stuff. I'll report back here after I do.

Question #3: What's so special about the Ron Francis Wire Works control panels?

Malc -- Oil, huh? Wow ... I never would've guessed THAT one. Will do. I'm gonna fix this whole setup like nobody's business by the time I'm done!

Thanks.

Alan
54 Chevy Pickup

I just got off the phone with Mark Hamilton of Mad Electrical -- what a NICE guy!

Re: The 30 amp circuit breaker ... he doesn't use them because they do become faulty and he's seen cars burn up in flames from old ones, etc., etc. ... he uses 18 gauge fusible links, he says, because they LAST for years and do the job well; they save your vehicle and protect all the important stuff from getting fried, and the ONLY time they fry up and need to be replaced is when something REALLY IMPORTANT needs your attention -- like a bad short somewhere. Mark says, when a fusible link goes, you need to find out the cause -- what made it fry -- and it's usually a fried wire that's shorting out; something that needs serious attention - not something that you want covered up by a fuse or breaker (where you may not know about it until it's too late).

THAT, along with me having a bad (brand new) 30 amp circuit breaker that I didn't trust to begin with, convinces me that the fusible link is the way to go.

PS - The 18 gauge wire I used as a fusible link is "totally cool" according to Mark.

Most guys don't want the hassle of having to repair a fusible link, but what does it take to keep a small spare length of 18 gauge wire and some connectors in your ride, and as Mark points out, you're not ever going to have to repair a fusible link unless there's something terrible happening that you wouldn't want a breaker or fuse "masking" your attention from.

Makes sense to me.

I bought all kinds of stuff! About $175.00 worth! But I got relays for my headlights, relays for my electric fan, a couple of his books about wiring, a kit to wire up my 3-wire 12si alternator the "right" way, a bunch of connectors, shrinkable tubing, fusible links, 10 feet of his 8 gauge "Tuff Wire"and two terminal boxes.

Hey - I spent 10 days rewiring my truck with the EZ-Wire kit ... now I'm augmenting all that from the battery to everything under the hood and making that job 100% instead of 85% ... way to go, Alan!

Alan
54 Chevy Pickup