Resistance too little or too much?

[minigts]

So if you were going to err on either side of having too much resistance or too little (not enough) which would be safer electrically? I know the starter relay requires some resistance, roughly about 24 ohms, but would 30 be ok?

[afsautoworx]

Too little...i believe resistance produces heat.

[minigts]

Well I was thinking of replacing the starter relay with one that I can fit in this fuse block, but the only one I have seen so far is a 30 ohm relay, so I didn' want to fry something.

Thanks for the response!!!

[afsautoworx]

Ohhhhh....i dont think youre talking about resistance. You mean amps i think. 30 amp relay? There probably is resistance on that relay but i wouldnt think it would be 30 ohms. maybe im wrong

[minigts]

Well, here's the deal. I have the factory starter relay and I want to move it to this fuse block. This fuse block has places for the factory relays like for the AC and fan relays. I opened one up and the AC and fan relays are IDENTICAL to the starter relay in the way it's designed. I Ohmed out the ends for contacts 1 and 2 on the starter and contacts 85 and 86 on the AC relay (the ends terminate the same way) and got different readings. The starter Ohmed out at 24 and the AC relay Ohmed out at ~83. So, I'm guessing this is important because the rest of it is just power in and power out.

When I say I Ohmed them out, I used a volt meter and set it to 200 Ohms and then tested the connection between the 2 points. Obviously I got different readings, so this has some impact.

[afsautoworx]

You need to open up the relay by supplying it with 12 volts on one lead and then ground on the other. If you look on the relay itself it should show u which ones to do that too. Once the relay is open then u can test the resistance across the other two leads. I dont think you should worry about resistance on a relay, only how many amps the relay is designed to carry. Check out this page http://www.1728.com/project3.htm. This should explain a lot. If the relay is working as it should and the relay is "closed" there should be infinite resistance between the B and C terminal. Dont know how much resistance there would be between v1 and v2, probably not much. If you already know all of this, then dont take this explanantion as an insult :D I think most relays also say on them how much theyre designed to carry

[minigts]

So you can't use an Ohm meter to measure the resistance on the two points? It gives a reading. I'm not good on electricity though, I'm just asking. I do appreciate the feedback, because I'd like to get this stuff moved.

[afsautoworx]

any questions you have if youre unsure just ask...love 2 help.

[minigts]

Here is what I have. The one on the left is the starter and the one on the right is the AC or fan relay. So they look the same, but where do I find info on how many amps the starter relay is?

Thanks for all the information.

[afsautoworx]

the cases that cover these relays up should tell u

[minigts]

Well there isn't anything stamped on either of the relays, but I'll look through my books to see if there is any info on them. Hopefuly I won't burn the car down!

[afsautoworx]

haha i hope not....i looked thru my book and couldnt find a rating on one. If i had to guess i would say it would prob be 90-120 amp relay. Ill look at my car tomorrow and see if my relays say anything on em. What car is this going on?

[turboshad]

The AC relay looks like a typical 30 Amp relay. Just by looking at it, the starter relay will be able to handle more current (amps). All a relay is is an electro-magnet that pulls a piece of metal towards it and make a connection between 2 points. It's easy to see in the picture of the starter relay. The big red spool is the spool of wires around a metal post comprising the electro-magnet. On the top is the piece it pulls down to make a connection where you can see there has been some arcing (the somewhat burnt spot on the upside down "L" shaped piece on the right). The resistance (ohms) you were measuring was the resistance of that coil of wire so that's really not too important, especially when it is that high. I would be more concerned if it were in the 0.5 ohm range which would suggest it could be shorted out somewhere on the coil. The resistance between the 2 contacts when they are touching idealy would be zero (dead short) but might have a little resistance from the burn marks. One way to figure out what the starter relay is rated for would be to find what the fusible link is rated at for thet starter circuit. I think thats in the service manual and would tell you that the relay could handle at least that much current and most likely more. If you were looking for a replacement that would be the number to shoot for.

To kind of answer your very first question, a higher resistance is safer b/c it will allow less current to flow through the wires. Too much current and the wires can melt which is why there are fuses rated to specific circuits to limit the total current.

Don't know if I talked too much but hopefully it helps.

DJ

[minigts]

You did talk too much. Please stop! Just kidding! Thanks for the info. You both have given me some good info to use to get this nipped in the butt! (I know it's nipped in the bud, but my girlfriend said that one time and I about spewed up the drink I had because I was laughing so hard)

[minigts]

And I looked in this fact sheet I have for my wiring and the ratings are as follows:

Ignition Feed J10 18 gauge (grey) fuse link 50amp 12 gauge (PK/BK*)

Ignition Feed J1 20 gauge (orange) fuse link 40 amp 12 gauge (RD)

The attachment below is the electrical page for the starter key circuit. However, NONE of the wires running to the starter are fused. The YL/BK* wire does run from the starter circuit shown in the picture, so which rating would be more appropriate for this application?

[turboshad]

That's because the start line at the column is just triggering the relay which will be low current. The link you want to look for is the one supplying power to the relay so either "A1" or "S5". Which ever one is not going to the starter motor.

DJ

[minigts]

AH HA!! It's S5 and maybe that's the reason that wire burned to a crisp when I tried to swap it out one time! LOL I was trying to replace that wire one time for some reason and I think I put a wire that had ZERO resistance on it and it lit up like a stream of gunpowder in about 2 seconds.


So that wire is 14 gauge. Would I need a fuse with such a high amp rating? I am not only new to electricity, but very stupid as well. I need teh edjukashun.

[turboshad]

If the link is blown then it should be replaced with an equivalent inline fuse. If the wire burnt up when you tried to replace it then there is probably a short somwhere in the circuit. If it smoked immediately even before you tried starting it then the wire between the link and the relay is shorted to ground. If it smoked when you tried cranking the starter then the short is between the relay and the starter motor or it is in the relay or motor itself. I can give some troubleshooting tips if you want, I just don't want to talk too long again.
DJ

[afsautoworx]

Shouldnt need to be fused

[turboshad]

Shouldnt need to be fused

How do you figure that? The whole point of any fuse or fused link is to prevent situations like
that's the reason that wire burned to a crisp By eliminating a fuse or link for that matter you are eliminating the safety systems put in place. Your call but I would much prefer replacing a fuse than watching my car go up in smoke.

DJ

[minigts]

HEY! It clicked. I got it now. I was focussing on the wire that runs from the starter key relay instead of the main power that is going to the starter. I was thinking that coil was touching the two wires that create the electromagnet when in fact it isn't and it simply is using that EM to pull the metal down to make contact with the main power source.

I got it now and I now understand why AMPS are more important than Ohms.

Thanks for the information guys!

[afsautoworx]

thought he was talking about the wire that runs from the starter relay to the starter solenoid. It doesnt look like its fused from the factory so why start now? if your burning wires up...its either from too much resistance (too small a wire/too much load) or like what u said short or 12v is getting grounded. Glad u understand now minigts, isnt electricity fun :thumb:

[turboshad]

I see, no prob. It is fused before the relay by a fuseible link so that takes care of it. I'm assuming that is the one that blew and he tried replacing with just a wire.

it simply is using that EM to pull the metal down to make contact
yes, now your getting it. Relays are essentially like light switches except the magnet does the job of your finger.

DJ

[minigts]

I can't remember what wire it was, but it was like a 14 gauge wire. Again, I was looking at resistance instead of amps and ended up putting a wire on there that got fried. Funny thing is, it happened after I turned the car off. Started it ran ok, then shut it off and POOF! It was gone.

So going to get a relay. I guess this question would be should I get a 50 amp or a 40 amp? In the picture above with the diagram, the yellow wire is closest to the 40 amp wire (RD) that runs to the starter key relay. It looks like the key turn would work where the run is before the start point. Meaning to me when you turn the key forward to actually start it that this is what the diagram is showing detailing. Please look at the picture here to see what I mean.

[Stevien1]

In the picture you posted, the a/c relay is a regular ISO type. Just about every car today uses them for a/c, radiator fans, ASD, and starter. You'll be fine using another "a/c" relay for the starter- remember it's only turning on the starter solenoid, not the starter itself. You'll want to put a fuse between B+ and pin 30 of the relay, just incase.

-Chuck James

[minigts]

In the picture you posted, the a/c relay is a regular ISO type. Just about every car today uses them for a/c, radiator fans, ASD, and starter. You'll be fine using another "a/c" relay for the starter- remember it's only turning on the starter solenoid, not the starter itself. You'll want to put a fuse between B+ and pin 30 of the relay, just incase.

-Chuck James

What is B+? And should I not get a 40 amp relay?

Just making sure. BTW, the people at Autozone I spoke to aren't too knowledgeable about what a relay is! Of course, I'm no expert but it saddens me to see how little people know about cars now a days who work in the field.

[turboshad]

What is B+?

Battery postive.

Steve1 is right. I forgot there was a selnoid on the starter itself. Kinda stupid that they use a relay to trigger a selnoid. Unless S5 or A1 is connected to ground (need a pic of the other page) and then it makes sense. Either way it seems a little beat around the bushish. In that case a relay similar to the AC relay would be fine. The seloid won't be drawing too much current.

DJ

[minigts]

S4 is connected to the block, the BR/YL wire. So if I get a fuse for the wire that runs back to the solenoid, what amp rating should it be? I would imagine a 40 amp fuse, but I still am not sure if I should use a 40 amp or 50 amp relay.

Again, thanks for all this help on the relay.

[turboshad]

Can you take a picture of the page on the left?

DJ

[minigts]

Here it is. I labeled where they go because one of the pages is continued on the previous and it just goes to the positive or B+ (:thumb:) cable with no fuse.

A friend told me that the relay acts like the fuse, so using an inline fuse is not necessary? It doesn't have one currently, but I think I see the point in doing the inline, more like a safeguard until I get this figured out.

[minigts]

Well the relay worked and the car started right up! Wee!!!!! Now to get rid of the solenoids!

[minigts]

Here is the finished product of the starter relay migrated to my fuse block!