Discussion Forum - Northstar Chevelle Club

4-door Chevelle · Super Poster

Need quick electrical help please

steve m · Member

Always run high amp draws right off the battery with a relay, them fans draw to many amps. Wired in many dual fan setups. Need to have a relay and something to trigger it like the ignition or temp switch.

seagrams72 · Active Member

Here is what I did:

http://www.oreillyauto.com/site/c/detail/LIT0/813030BP.oap?keyword=breaker&pt=N0227&ppt=C0335

http://www.oreillyauto.com/site/c/detail/BLZ0/DF005W.oap?keyword=30+amp+relay

Wire the battery (or whatever good source) to the breaker than the breaker to the relay. Then from then relay to the fan. The relay can be switched on and off by a thermo switch, toggle, or just an accessory on source. Mine ran great last year and I am finishing the wiring on my new fans this weekend with the same setup.

All the fan wiring kits are going to include these parts you can buy for under $10.

Chris R · 2K+ Club

You definetly need to have relays switch on your fans without using the battery cables to supply power directly.

John D · 2K+ Club

I'll put a diagram together for you later today - something in plain English - not techno/electron speak. For now take a look here: JD's Basics 2

4-door Chevelle · Super Poster

I left that little piece out of my detai, sorryl ... I have relays, separate feeds and 30 amp fuses for each electric fan. I am actually really focused on whether the alternator should go to the battery (aftermarket) or the horn relay (stock). I was up much of the night for other reasons so I read through all my notes again. The voltage sensing that happens in our cars relies on the draw at the horn relay so I thing I need to upgrade my wire from tge alt to horn relay and the horn relay to the starter. I hope I did not damage anything.

John D · 2K+ Club

Something caused that link to melt/pop - so there's a problem somewhere... One of the leads/wires in the alt to horn rly circuit, or horn rly to starter post circuit has a serious short to ground. Look for cuts, nicks, chafes, melts, or pinches. Those things just don't arbitrarily happen.

I'd suggest going to 10-Ga. wire for each of these circuits. (and be sure to replace the fusible link!)

4-door Chevelle · Super Poster

I will run a new 10G wire from the alt to horn relay, then a new 10G wire from the horn relay to the starter wire now relocated to remote solenoid with a 14G fusible link. I am actually going to peel back all of the factory wrap to see what the heck is in there. Then I can get back to work on my car!?!

Bowtieman427 · Active Member

In you option #2 where is your sence wire located ? You had a high current draw somewhere. This could of happened from short low voltage drop somewhere. If you have a high out put alt and stock wiring the alt could have over current the wire if the sence wire showed a low drop in voltage (demanding more current) , or you could have a short. The short would most likley be in the wire between the relay and starter. I would think
1) How high of output alternator ?
2) Do you have a current meter or voltage meter in car ?
3) Any battery issues what is the voltage on battery ?
4) Fans on fuses now how ar they wired mentioned they were not running should they have been running when this event took place ?
5) how did you maintain the gen light in option 2 (non of the old regulator wires shorted) ?
6) Did you check the alternator after event ?

large voltage drop short or what ever made curent demand very high back to battery.

Lost in the 60s · President

Wow, this is crazy to know it happened right after you left here....

The starter did give that high pitch grind like it's a little tight when you fired it up to leave, but I didn't get the impression it stuck engaged. That can cause this situation too OR, do you have an AMP gauge installed ? They are a source of shorts like this too.

Sorry to hear about all the grief and tow bill....at least the back window didn't blow out.

4-door Chevelle · Super Poster

The voltage regulator F plug is a blue wire, the 2 plug is a yellow wire and both go to the connector on the back of the alternator. The 3 plug is a red wire goes to the horn relay with a fusible link just before the horn relay, according to what I read this is the sensing wire. the 4 plug is a brown wire and I can't tell for sure where it goes.

The alternator wire is a 10G wire and it hits a Y junction just before the horn relay. The starter wire is a 8G wire that has the fusible link at the starter and connects to this same Y junction just before the horn relay. This is the fusible link that fried off completely. From the Y junction headed towards the alt about 6 inches of the wire coating melted off, I assume the fusible link finally burned off and that is why only 6 inches melted.

I am hesitant at this point. I want to run new 8G wires but want to remove the Y junction and go straight to the horn relay for both wires. I feel like I want to put a fusible link/30A breaker/30A fuse for each wire for some reason since I want to exclude that Y junction.

135AMP alternator
I do have a volt meter, connected to the ACC spade in the fuse box, it reads high ... like up at 18, soon to be disconnected
Battery voltage is at 12.88
Horn relay with 8G wire to 2-port fuse box with 2 30A fuses, 1 for each fan and it was cool enough at 60mph they weren't on
No idea about the Gen light
I will check the alt after I get it running

I was quite pleased the back window didn't blow out and being I short squall blew through while I was sitting there I was confident my trunk was dry!

4-door Chevelle · Super Poster

Bowtieman427 · Active Member

Are you still connected to an external voltage regulator ????
If you were running 1 wire your alternator has a regulator in it do not connect to exterenal regulator. I am assuming you setup with internal Voltage regualtor. What you describe sounds like you have external regualtor still (or still in the car) in car and are connecting to it ?
Y junction you describe does not sound typical to internal regualtor setup. True 1 wire is only done on internal regulater in alternator and turns on at x rpm and stays on till shut off.
#2 should be your sence
Blue and brown would be on the external regulator. when the external is bypassed they can be tied together to give generator light. This is why I asked how you got a generator light.
check this out
http://www.chevelles.com/techref/ftecref14.html

The 18 Volt reading is very interesting.

-- Edited by Bowtieman427 on Thursday 21st of April 2011 11:01:12 PM

Chris R · 2K+ Club

If you've got 18 volts. Your voltage regulator is shot big time. Is the alternator internally regulated or externally regulated?

4-door Chevelle · Super Poster

The alternator I bought was for an external voltage regulator which I have. With the #2 wire part of the 2 wires that make up the connector at the back of the alernator that can't be the voltage sense wire that regulates the alternator. I do also have the voltage regulator from my old Chevele, might do some testing with that plus take some readings at different points in the system.

Chris R · 2K+ Club

Well since you have an externally regulated alternator and your amps are way too high. Verify your wires and connections are in good shape and get a new regulator. They are cheap and worth the upgrade. Todays external regulators are electronic controlled instead of the old transistor style they were originally.

Chris R · 2K+ Club

I also had this saved in my Favorites. Should help with the electric fans.

http://www.aaroncake.net/rx-7/efaninstall.htm

Bowtieman427 · Active Member

seagrams72 wrote:
Here is what I did:
http://www.oreillyauto.com/site/c/detail/LIT0/813030BP.oap?keyword=breaker&pt=N0227&ppt=C0335
http://www.oreillyauto.com/site/c/detail/BLZ0/DF005W.oap?keyword=30+amp+relay
Wire the battery (or whatever good source) to the breaker than the breaker to the relay. Then from then relay to the fan. The relay can be switched on and off by a thermo switch, toggle, or just an accessory on source. Mine ran great last year and I am finishing the wiring on my new fans this weekend with the same setup.
All the fan wiring kits are going to include these parts you can buy for under $10.

This is a great idea. Most relays like this are rated 30 A and looking at there construction and the fact that fans run on electric motors which have very high inrush (startup current) it may be best to wire it up with 2 relays and two brakers. use 10ga for each lead in from source. Benifits of this if one fan dies you still have another turning. If you do not want to source the parts yourself buy kit. Jegs has a kit search on it you can look at there basic schematic you can use and get own parts.

I would also ditch the external regulator and go with an internal regulated alternator. I got a Powermaster that can be wire 1 wire 2, or 3 (with idiot light if you wire it) you will have to do some mods but form the looks of your photo you got it all apart already.

IMO Many alternators today are junk I believe you get what you pay for. In our old cars the electrical system is not thought of until there is a problem, unfortunatly the problem usually results in smoke, burn or will not run.

Also think if you are running dual fans and 135A alternator time to upgrade the old 10ga to 8ga

John D · 2K+ Club

I scribbled this out on Thursday after work - forgot to send it.

Diagram on how I would have the fans/relays/switches wired. All circuits are either fused or breaker'd, and gives the option of a manual override on the temp sensor.

4-door Chevelle · Super Poster

I have 8ga from alt to Horn Relay, I have 8ga from Horn Relay to battery side of remote solenoid. I do have 19 volts in the system when running so there is an issue! I picked up a replacement external voltage regulator, installed it and now I am down to 15.10 volts but the new unit was smoking a little bit so I shut it down. I disconnected the wire from the alt to Horn Relay and ran one right from the alt to the + battery post like the alt experts wanted. I am still running 15.10 volts and the new unit was still smoking a little bit but it did not feel warm anywhere, maybe it was just burning off the dust but I did shut it down after about 1 minute.

This whole alt, electric fans, relays, sensors ... everything I now have in the new Chevelle worked fine on the old Chevelle.

As a test I guess I could put in the old stock alt to see if I am now at 12-14 volts.

I am running out of time...

4-door Chevelle · Super Poster

With the voltage regulator from the old Chevelle installed in the new Chevelle I am at 14.75 volts. Is that still too high?

SShink · 3K+ Club

In my experience, that's about right and 'normal'. Especially if there is a load on it like having the headlights on.

Bowtieman427 · Active Member

14.75 is ok.
John D. I did things a little different have not tested it yet. I have 6 ga from internal reg Alt to horn realay. 6 ga Horn relay to starter with 175A fuse. 6ga Horn realy to 2x30A breakers to 2x30A relay to fans and 2x20A breakers to 2x30A relays to hi and low beams. Nothing is connected directly to bat. accept Mallory ign system and starter. My volt sence off Alt is at Horn relay also. Horn relay will be currnet distribution point source. I hope it works have not tested it yet. Thought is bat is a potential energy source to keep the potential constant alternator will feed the current to the loads NOT the Bat from horn relay point source.