Hi speed ac fan wiring burning

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pontiacgp

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I will have to disagree with you on that. Have you ever worked on any 86-93 Fords with the 2G alternator that has the side connector spades? That connector contained the power feeds and would build up resistance and melt the plugs and occasionally cause fires. It was such a great design that Ford went back to bolt on power connections on the 3G and later alternators.
The late model GM trucks from 99-06 had the same issue with the blower resistor. The spades were too small and would over heat and melt the plug and the plastic resistor housing. I used to solder the wires directly to the power and ground terminals on those and never have the issue again. Been wrenching for a living for a long time. Spades have their place, but high amperage power feeds (or even the ground side) circuits are terrible for them. Why do you think almost every alternator out there uses a bolt on terminal for the power feeds?

you are the only person I know who have issues with spade connectors. I have had a spade connector on the heater wire for about 5 years with no issues.
 

pontiacgp

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Yep its just me. ;)

you might want to do a bit of reading on the subject... :popcorn:

" A crimped spade terminal actually creates a metal-metal colloidal bond at the surface between the wire and the terminal, and if done right, no gas remains between the surfaces. This ensures longevity and safety, making this the preferred mechanism in industrial implementations. "
 

gnvair

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you might want to do a bit of reading on the subject... :popcorn:

" A crimped spade terminal actually creates a metal-metal colloidal bond at the surface between the wire and the terminal, and if done right, no gas remains between the surfaces. This ensures longevity and safety, making this the preferred mechanism in industrial implementations. "
:LOL:
 

Neill

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Mar 7, 2014
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I think a lot depends on who makes these connectors. Inexpensive ones do lose their tension, not to mention corroding prematurely. I buy terminals from a good hardware store. The cheap 'box of assorted sizes' sold elsewhere are usually junk now.
 
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CopperNick

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+1 on the current issue. Wires get hot mostly due to excessive resistance in the circuit. Blame for that can be old and decayed wire, bad connections, bad grounds, wire that is undersized for gauge and application, and old components like the motor mentioned above.

As for the addition of an aftermarket relay

s-l1000.jpg


This picture is of a typical 5 pin relay socket. Basically all a relay is, is a type of switch that uses a low power circuit to initiate or close a second circuit in the relay that is designed and built to handle power delivery to a high demand circuit, such as power window motors, or windshield wipers or a starter. For the sake of conversation here, make the assumption that this relay is being put in a typical GM starter motor circuit. In the above picture there are two pins designated #85 and #86. These constitute the low power side of the relay. In a factory design, power to the starter solenoid and starter motor goes through the key switch before it gets to those destinations. The further current has to travel before it reaches whatever it is expected to operate, the higher the resistance will be in the circuit and the greater the voltage needed to deliver enough power that whatever is being actuated will actually work. With the relay wired into the starter circuit, the key and its wiring no longer have to deal with heavy voltage or current. The power would come from the battery, but instead of going to the key directly it would go instead to pin 86 and then, when the key was turned to start, the relay would close and power would flow to ground, aka 85. The heavy duty or high power side of the relay is handled by # 87/87A, and #30. As shown in the diagram, #30 is the power in side of the relay. In the starter motor example, this would be power coming directly from the positive side of the battery. When the key is turned and the relay is actuated, the second high load circuit is activated that sends the power coming in on 30 out again on either 87 or 87A (if multiple events need to occur at the same time) In my example, that would be power going to the solenoid and the starter motor to get the starter cranking the engine over.
Here's the thing. The key side of the relay doesn't need heavy gauge wire, it can now live quite happily with the stock gauge wires it was fitted with by the factory as they no longer have to deal with high/heavy current or voltage. The power side of the relay can be wired using heavier than stock wire, such as 12 or 10 ga. wire, as opposed to the stock/OEM 26 or possibly 14 ga that the harness was laced with. Moreover, the wiring for heavy side of the relay also becomes shorter and more direct because it no longer has to travel into the cabin and to the switch and wherever else before it finally gets to the starter. This translates to less resistance in the heavy circuit due to it being both shorter and made of a higher gauge wire. Current flows more easily and less voltage is needed to make the delivery. The net consequence is that the starter gets more power to spin up more quickly and strongly, creating less internal heat due to being able to work more efficiently and the engine turns over and fires sooner. The battery is also happier because the draw on it is less over time meaning it takes a shorter amount of time to recharge after the engine is running.

Basically you can insert a relay into almost any circuit where there is excessive draw and current drop. If you feel like being contrary, 85 and 86 can each do the others job; they are not dedicated in terms of which handles power in and which is ground. And for those who grumble that all this is well and good but how do I figure out the numbers if I don't have the cute socket or similar shown above? if you flip the relay over to display the pins, you will discover that each pin has a number sitting beside it. As for 5 pin versus 4, the 4 pin just has one #87 pin, meaning it is designed to handle only one activity or event. The five pin would see action in a high/low headlight situation with one 5-pin handling the low beams and a second the highs.

Enough. This takes longer to illustrate than it does to fabricate and install the harnesses and hang the relay somewhere. Bleah.

Nick
 
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oldsofb

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There was no pic of what wire is having the problem. I may have missed it, but I don't think the wire color was mentioned either. A pic goes a long way.

You said the High Speed Relay was OEM. Does that mean the original one or a stock replacement?

Since I'm not sure of the wire, have you removed the Blower Resisters from the case and checked their condition?

Hutch
 
Oct 14, 2008
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+1 on the current issue. Wires get hot mostly due to excessive resistance in the circuit. Blame for that can be old and decayed wire, bad connections, bad grounds, wire that is undersized for gauge and application, and old components like the motor mentioned above.

As for the addition of an aftermarket relay

View attachment 154575

This picture is of a typical 5 pin relay socket. Basically all a relay is, is a type of switch that uses a low power circuit to initiate or close a second circuit in the relay that is designed and built to handle power delivery to a high demand circuit, such as power window motors, or windshield wipers or a starter. For the sake of conversation here, make the assumption that this relay is being put in a typical GM starter motor circuit. In the above picture there are two pins designated #85 and #86. These constitute the low power side of the relay. In a factory design, power to the starter solenoid and starter motor goes through the key switch before it gets to those destinations. The further current has to travel before it reaches whatever it is expected to operate, the higher the resistance will be in the circuit and the greater the voltage needed to deliver enough power that whatever is being actuated will actually work. With the relay wired into the starter circuit, the key and its wiring no longer have to deal with heavy voltage or current. The power would come from the battery, but instead of going to the key directly it would go instead to pin 86 and then, when the key was turned to start, the relay would close and power would flow to ground, aka 85. The heavy duty or high power side of the relay is handled by # 87/87A, and #30. As shown in the diagram, #30 is the power in side of the relay. In the starter motor example, this would be power coming directly from the positive side of the battery. When the key is turned and the relay is actuated, the second high load circuit is activated that sends the power coming in on 30 out again on either 87 or 87A (if multiple events need to occur at the same time) In my example, that would be power going to the solenoid and the starter motor to get the starter cranking the engine over.
Here's the thing. The key side of the relay doesn't need heavy gauge wire, it can now live quite happily with the stock gauge wires it was fitted with by the factory as they no longer have to deal with high/heavy current or voltage. The power side of the relay can be wired using heavier than stock wire, such as 12 or 10 ga. wire, as opposed to the stock/OEM 26 or possibly 14 ga that the harness was laced with. Moreover, the wiring for heavy side of the relay also becomes shorter and more direct because it no longer has to travel into the cabin and to the switch and wherever else before it finally gets to the starter. This translates to less resistance in the heavy circuit due to it being both shorter and made of a higher gauge wire. Current flows more easily and less voltage is needed to make the delivery. The net consequence is that the starter gets more power to spin up more quickly and strongly, creating less internal heat due to being able to work more efficiently and the engine turns over and fires sooner. The battery is also happier because the draw on it is less over time meaning it takes a shorter amount of time to recharge after the engine is running.

Basically you can insert a relay into almost any circuit where there is excessive draw and current drop. If you feel like being contrary, 85 and 86 can each do the others job; they are not dedicated in terms of which handles power in and which is ground. And for those who grumble that all this is well and good but how do I figure out the numbers if I don't have the cute socket or similar shown above? if you flip the relay over to display the pins, you will discover that each pin has a number sitting beside it. As for 5 pin versus 4, the 4 pin just has one #87 pin, meaning it is designed to handle only one activity or event. The five pin would see action in a high/low headlight situation with one 5-pin handling the low beams and a second the highs.

Enough. This takes longer to illustrate than it does to fabricate and install the harnesses and hang the relay somewhere. Bleah.

Nick
I would like to beat the idiot who thinks a red ground and a black positive is a good idea.
 
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pontiacgp

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Mar 31, 2006
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must be true that ignorance is bliss....
I would like to beat the idiot who thinks a red ground and a black positive is a good idea.

I thought I had a explanation for that but when I saw they had a blue wire I'm stumped...... :popcorn:
 
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