Brew Posted July 13, 2021 Share Posted July 13, 2021 Anyone else have this issue? I think it is the control for the blower motor. I can replace it but wondered if anyone knows why it’s doing that? It was like that when I bought the car and I replaced it before so this is second time it has done that. I see no contact with any other spade on back of controller. Quote Link to comment Share on other sites More sharing options...
MCfan Posted July 13, 2021 Share Posted July 13, 2021 According to my '70 wiring diagram, those two wires, Light Blue (LBL) and Yellow (Y) are both 18 ga and connect the Heater Resistor to the Heater Connector (possibly on the A/C controller?). Since it is a direct two-wire connection between only two plugs, I suspect one of the following: 1. The heater resistor is faulty. (my strongest suspicion) 2. One of the wires is in the wrong position on one of the plugs which may compromise the circuit. (swapping both wires on both plugs should have no effect as they are both 18 ga) 3. The plugs are reversed (may not be possible if they are different physical shapes). I have attached a photo of the page in the Wiring Diagram that I referenced. The circuit I think you are concerned about is shown in the diagram as the third one down from the top. Since that circuit is specifically for the heater, I doubt that it matters if you also have A/C. It is still possible that this wiring diagram is not correct for your particular car/options. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 I don't think that diagram applies Dennis, as it's for a non-A/C vehicle. The plug D.B. has in his hand should be a 3 position plug, and it looks like evidence of a prior repair shows the tan wire by itself on the fan switch (yellow crimp terminal). It appears the connector is broken/damaged. As such, the wires are of a larger gauge as well it seems. The diagram of an A/C setup as in your other thread would be correct, I believe. High resistance like Dennis mentioned could cause it to melt possibly. Pop the blower resistor out of the engine compartment box & see if it's all rusty or corroded. That could cause issues. Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 That’s interesting because 1 hour ago, jft69z said: I don't think that diagram applies Dennis, as it's for a non-A/C vehicle. The plug D.B. has in his hand should be a 3 position plug, and it looks like evidence of a prior repair shows the tan wire by itself on the fan switch (yellow crimp terminal). It appears the connector is broken/damaged. As such, the wires are of a larger gauge as well it seems. The diagram of an A/C setup as in your other thread would be correct, I believe. High resistance like Dennis mentioned could cause it to melt possibly. Pop the blower resistor out of the engine compartment box & see if it's all rusty or corroded. That could cause issues. That may be it. I replaced blower motor resistor & it was pure rust. I have not run the ac again since but ran blower to test because I replaced it. I am going to separate this connector into 2 individual spade connections & test it out. I’ll start on that as soon as my heater coil is back in. Did I mention I hate cars? 😁 Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 5 minutes ago, Brew said: Did I mention I hate cars? 😁 Me too, more than most people think. Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 13, 2021 Share Posted July 13, 2021 2 minutes ago, jft69z said: Me too, more than most people think. You’re not alone Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 Just now, Dtret said: You’re not alone I know, misery loves company 😭 Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 13, 2021 Share Posted July 13, 2021 1 minute ago, jft69z said: I know, misery loves company 😭 The funny thing is—— we keep doing it. Just how many times can I get kicked in the (insert adjective here) before I learn. Lol Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 1 minute ago, Dtret said: The funny thing is—— we keep doing it. Just how many times can I get kicked in the (insert adjective here) before I learn. Lol The same amount as me apparently. We just aren't able to let someone else do work for us, if it's something we're capable of doing ourselves. That doesn't even include the years we both worked on other people's vehicles (though part of the reason I hate working on them now). Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 2 hours ago, jft69z said: I don't think that diagram applies Dennis, as it's for a non-A/C vehicle. The plug D.B. has in his hand should be a 3 position plug, and it looks like evidence of a prior repair shows the tan wire by itself on the fan switch (yellow crimp terminal). It appears the connector is broken/damaged. As such, the wires are of a larger gauge as well it seems. The diagram of an A/C setup as in your other thread would be correct, I believe. High resistance like Dennis mentioned could cause it to melt possibly. Pop the blower resistor out of the engine compartment box & see if it's all rusty or corroded. That could cause issues. An electrical engineer I know just told me it is unlikely that corroded resistor caused the melting plug. I guess we will see Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 15 minutes ago, Brew said: An electrical engineer I know just told me it is unlikely that corroded resistor caused the melting plug. I guess we will see High resistance causes heat. If the wires and connector current carrying capacity is exceeded due to higher current flow, bad things happen. Your 14 ga. wires are typically good for up to 15 amps, the 16 ga. wire up to 10 amps. If it were me, I'd hook up an ammeter in the circuit and check the actual draw. I'd also use an ohmmeter across your blower resistor contacts and see what you come up with. Maybe compare the old, rusty one to the new one if you kept it. Look at how that resistor is put together, the actual wires are just crimped to the terminals, not soldered, etc. Add rust & corrosion at that physical joint=higher resistance. Could also be a poor connection at the plug, and also a bad blower motor that's drawing excess current. Again, measuring actual current is the best place to start troubleshooting. Then you know what you're dealing with. Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 10 minutes ago, jft69z said: High resistance causes heat. If the wires and connector current carrying capacity is exceeded due to higher current flow, bad things happen. Your 14 ga. wires are typically good for up to 15 amps, the 16 ga. wire up to 10 amps. If it were me, I'd hook up an ammeter in the circuit and check the actual draw. I'd also use an ohmmeter across your blower resistor contacts and see what you come up with. Maybe compare the old, rusty one to the new one if you kept it. Look at how that resistor is put together, the actual wires are just crimped to the terminals, not soldered, etc. Add rust & corrosion at that physical joint=higher resistance. Could also be a poor connection at the plug, and also a bad blower motor that's drawing excess current. Again, measuring actual current is the best place to start troubleshooting. Then you know what you're dealing with. I’m not much of an electrician but I’ll try to do that stuff. Thank you for the suggestions. Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 13, 2021 Share Posted July 13, 2021 Engineers? Mostly great people but....remember this is 50 years of wear and tear. An aging electrical system. Rust and corrosion cause resistance. I’ve pulled many wires apart that looked good on the outside but were green on the inside Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 2 minutes ago, Brew said: I’m not much of an electrician but I’ll try to do that stuff. Thank you for the suggestions. If you're not comfortable doing it, ask for help. Trying to measure current with an ammeter isn't like just measuring voltage. If you can find a clamp on ammeter that simply clips around the wire, that's easier. I have all that stuff here, but I've also been doing that stuff for over 40+ years between the military, industrial, and automotive. PM me if you want my phone number. 2 minutes ago, Dtret said: Engineers? Mostly great people but.... Yeah, my thoughts exactly, lol. Again, with over 40 years of experience in the instrument/electrical/automotive world, I've dealt with hundreds of them maybe? Hmmmmm...I'll just leave it at that. Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 18 minutes ago, Dtret said: Engineers? Mostly great people but....remember this is 50 years of wear and tear. An aging electrical system. Rust and corrosion cause resistance. I’ve pulled many wires apart that looked good on the outside but were green on the inside This guy is a really good one. He is retired. In his 70’s. He used to build torpedoes for the navy. Designed & built electrical systems for them. He’s not a drawing room only type of engineer. Very hands on. But I know what you mean nevertheless Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 22 minutes ago, Brew said: This guy is a really good one. He is retired. In his 70’s. Old school, that's good, lol. Some of the one's I've dealt with over the years would scare you. Downright dangerous. Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 I know what you mean! Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 1 minute ago, Brew said: I know what you mean! Northstar V8, been there before, lol Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 I’m convinced that automotive engineers all live in houses without numbers & have unlisted phone numbers. 😡 1 Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 I had one young engineer tell me that " she had the degree", meaning she knew more than those of us that had been around a long time. Told her I had more time on the toilet than she's been in industry, let alone the planet, lol. Said I could use that degree to wipe myself. That, plus I called the trailer they were all in a 'daycare center for engineers'. The superintendent of maintenance wasn't too amused with my answers 🤣. Problem was, the stuff she was trying to do would have literally resulted in an explosion. 1 Quote Link to comment Share on other sites More sharing options...
Brew Posted July 13, 2021 Author Share Posted July 13, 2021 I’ll show that to my wife. An ENGINEER! 🤣 Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 Just now, Brew said: I’ll show that to my wife. An ENGINEER! 🤣 Great, I made another friend today, hahahaha Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 13, 2021 Share Posted July 13, 2021 3 minutes ago, jft69z said: Great, I made another friend today, hahahaha See I just need to stop adding input. I just got kicked in the ( insert adjective here) again. I guess I didn’t make any new friends either. Karen always tells me to stop saying what I think. I’m thinking she might be on to something here. Lol. Quote Link to comment Share on other sites More sharing options...
jft69z Posted July 13, 2021 Share Posted July 13, 2021 1 minute ago, Dtret said: See I just need to stop adding input. I just got kicked in the ( insert adjective here) again. I guess I didn’t make any new friends either. Karen always tells me to stop saying what I think. I’m thinking she might be on to something here. Lol. Nah, we love you just the way you are 😍 Quote Link to comment Share on other sites More sharing options...
Dtret Posted July 13, 2021 Share Posted July 13, 2021 Just now, jft69z said: Nah, we love you just the way you are 😍 O shut up. Quote Link to comment Share on other sites More sharing options...
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