FordFETruck Posted January 28 Share Posted January 28 Yes, that would be an interesting test. But I'm going to leave it where it is as I've gotten a dramatic improvement, even though there's a bit left to be had if someone really wanted to pursue it. That .8v drop is across several connectors, wires, relays, etc. But it could be less if someone really wanted to work on it. However, these #'s are with the new 50A relays, so it isn't likely the drop is across the relays themselves. But it might well be across the relays' connectors since Steve pointed out that they carry a special socket they recommend if you are going to try to put 50A through those relays. And then there are the connectors to the fuse. So right there you are talking about 6 connectors, but then there's the "little" connector to the blower motor itself, which has smaller terminals than the relays or the fuse. So I'm happy with the results I got. I just installed a new blower motor in my truck, it helped a bit with speed as the old one was worn out and the bearings were junk but the motor still does not spin as fast as I think it should. Defrost works but it's about half as effective as any other car I have, and the blender works. I guess I should take the connectors apart and clean them? Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 28 Share Posted January 28 Yes, I do see that they have a very wide range of products. They even have the Cole-Hersee 48530 battery isolator that I'm using on Big Blue. And other products I've never even heard of. And, they may well be right about the Bosch 0 332 019 103 relay being a 50A unit, in spite of what this "Bosch catalog" says. I'd forgotten that we have a Bosch catalog on the site (Documentation/Electrical/Relays & the Bosch Relays tab), and that catalog says that the 0 332 019 103 is indeed a 50A unit, as you can see below. And that page shows the contact voltage drop, both new and "after life", whatever that is. At 12V & 10A those are .05v and .08v respectively. In fact, if you were to scroll on down in that catalog you'd find that the 30A & 40A-rated standard relays have the same voltage drop specs at 10A. So I must be doing something wrong in my testing since I'm seeing .3 to .7V drop, which is about 10 times more. I guess my wiring might make up part of that, but I wouldn't think it would account for all of it - especially on the relays that had more drop. Given that I'm trying to come up with better testing approaches and would welcome input. For instance, I've been pulling the relays in and then applying the load. Maybe I need to make the relay switch the load? Thoughts? I'm still wondering about your voltage drop. It's almost like there's a diode in the circuit...(at least those readings are about what you should see, if there was) Did you ever locate the mystery ground that doesn't appear in the EVTM? I don't have a Bullnose to look at. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 28 Share Posted January 28 The blender works. I guess I should take the connectors apart and clean them? The blend door works, but are there any other foam joints where air could be leaking out? You've got to remember these trucks were designed in the 1970's and used blow or roto moulded parts with more thought about how to make them fit and be produced on tools available 45 years ago. Smooth flow and velocity were more of an afterthought. There's no doubt that NVH have come a LONG way since then. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 28 Author Share Posted January 28 The blender works. I guess I should take the connectors apart and clean them? The blend door works, but are there any other foam joints where air could be leaking out? You've got to remember these trucks were designed in the 1970's and used blow or roto moulded parts with more thought about how to make them fit and be produced on tools available 45 years ago. Smooth flow and velocity were more of an afterthought. There's no doubt that NVH have come a LONG way since then. Right, looking at the ductwork they didn't give much, if any, thought to getting the air to flow smoothly or rapidly. But I assure you that the wiring, connectors, and switches are a huge part of the problem. However, fixing that is a pain - unless there are any of the kits left like Jim installed on his truck. As for there being a diode, I sure don't know where it is. You are right that the drop I'm seeing is about right for that, but since all the wiring now is mine save for the last few inches of the motor's whip I don't think there is one. But I also don't understand where a .8V drop is coming from. Nor did I find that ground. I really just ignored it and provided my own. Link to comment Share on other sites More sharing options...
FordFETruck Posted January 28 Share Posted January 28 The blender works. I guess I should take the connectors apart and clean them? The blend door works, but are there any other foam joints where air could be leaking out? You've got to remember these trucks were designed in the 1970's and used blow or roto moulded parts with more thought about how to make them fit and be produced on tools available 45 years ago. Smooth flow and velocity were more of an afterthought. There's no doubt that NVH have come a LONG way since then. I have not found any leaks in the system other than the vents themselves but listening to the motor I think it should spin faster especially on high. The reason why I started questioning it, is the heater in my 64 Galaxie, which is an even more crude HVAC system makes the trucks heat/defrost look and feel like a horrible joke both blower fan speed wise and the vent performance. I think a truck that's 22 years newer than that car should be able to keep up with it on defrost. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 28 Author Share Posted January 28 I have not found any leaks in the system other than the vents themselves but listening to the motor I think it should spin faster especially on high. The reason why I started questioning it, is the heater in my 64 Galaxie, which is an even more crude HVAC system makes the trucks heat/defrost look and feel like a horrible joke both blower fan speed wise and the vent performance. I think a truck that's 22 years newer than that car should be able to keep up with it on defrost. If you want to measure the voltage going to the blower motor you might discover why it is blowing so little. But measuring the voltage isn't all that easy as the connector for the motor doesn't provide any easy access. I made little jumpers that plug into the female side and have alligator clips to go on the male terminals to give me access. Or you could just bite the bullet and put relays in. I'm certain you'll like the results as I brought the voltage up by 50% on mine, which made a huge difference. Link to comment Share on other sites More sharing options...
FordFETruck Posted January 28 Share Posted January 28 If you want to measure the voltage going to the blower motor you might discover why it is blowing so little. But measuring the voltage isn't all that easy as the connector for the motor doesn't provide any easy access. I made little jumpers that plug into the female side and have alligator clips to go on the male terminals to give me access. Or you could just bite the bullet and put relays in. I'm certain you'll like the results as I brought the voltage up by 50% on mine, which made a huge difference. I tested the voltage at the motor. The new blower motor has a rubber grommet over the motor end of the connector and I could get right to the metal part of the connectors. I am getting .5 volt drop from battery to blower motor connector running on high with engine on or off. With blower motor disconnected I only get .1 volt drop through the factory wiring. I also ran jumpers straight from the battery to the blower motor WHILE it was running on high and the motor barely sped up enough to notice a change in sound. Looks like my system does work pretty well since there was barely a RPM difference from factory wiring to jumping straight to the battery. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 28 Author Share Posted January 28 I tested the voltage at the motor. The new blower motor has a rubber grommet over the motor end of the connector and I could get right to the metal part of the connectors. I am getting .5 volt drop from battery to blower motor connector running on high with engine on or off. With blower motor disconnected I only get .1 volt drop through the factory wiring. I also ran jumpers straight from the battery to the blower motor WHILE it was running on high and the motor barely sped up enough to notice a change in sound. Looks like my system does work pretty well since there was barely a RPM difference from factory wiring to jumping straight to the battery. Wow! That's great. I'm amazed, but happy for you. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 31 Author Share Posted May 31 Wow! That's great. I'm amazed, but happy for you. Time for an update. As I've been re-wiring the passenger side PDB I was planning to use the 2nd spot in the box for a diode to protect the relay that grounds the blower in high. But that got me to thinking about how a snubber diode should be used on a motor and I realized I'd implemented the first diode incorrectly. The first diode, which is actually D2 in the PDB, was wired from the positive lead of the motor to ground. But, the "low side" of the motor is only truly grounded in high, so if the ground relay isn't closed then the diode is trying to snub the excess current through the resistor pack. And while that does some snubbing it won't be all that it could be. So now I'm going to wire the diode from the positive lead to the negative lead of the motor. So whenever the power relay is cut and the back EMF hits the diode will snub it regardless of the speed setting on the control switch. Link to comment Share on other sites More sharing options...
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