Gary Lewis Posted February 24, 2020 Share Posted February 24, 2020 But I think you need to check this using the same ground in the harness. If you check voltage against a chassis ground the data is next to meaningless. I intend to implement a hot side relay as soon as I get back into my little PDC. I was thinking he could check the ground at C603 back to the battery post. Obviously the relay should provide essentially no voltage drop, but since the stock wiring provides the ground back through the blower motor switch I expect some voltage drop. But Scott has some videos for us of before and after that he plans to post, so let's see what they sound like. Link to comment Share on other sites More sharing options...
kramttocs Posted February 24, 2020 Share Posted February 24, 2020 I was thinking he could check the ground at C603 back to the battery post. Obviously the relay should provide essentially no voltage drop, but since the stock wiring provides the ground back through the blower motor switch I expect some voltage drop. But Scott has some videos for us of before and after that he plans to post, so let's see what they sound like. Had a chance to hook the relay up yesterday. I am really liking the Bussman ssVEC. Made hooking it up a snap. I picked up a new motor since the old one did not survive the exploratory surgery to see if I could powder coat it. The new one I got was 4W7Z-19805-AA (MM-929). This also required a jumper wire: Motorcraft Fuel Pump Connector Wiring WT-56853 (4W7Z-14A411-B) Wasn't really happy with the jumper wire design as it mixes wire gauges but I guess the relay mod mitigates that concern on the hot side although not the ground* Since the jumper is nothing more than two connectors spliced together and it's all right beside the relay block, it was pretty straightforward to split the splice, add MP 280 female terminals and plug it in. Ideally it would be in the grey plug since the jumper wire was pretty short but the ssVEC is split between two inputs (I am using one for the main battery and one for the aux) and the way I have it wired, the grey is aux powered. Here you can see the jumper wire connecting to the factory plug (white to black connector) and how I split it to go into the ssVEC. Sorry, lighting isn't the greatest. As Gary mentioned, I took some videos to try and show the sound difference between the two. Factory: Relay: If you keep both videos paused, set the factory one to 19sec and the relay one to 14sec, then play them one at a time right after each other you can hear the difference. If there are any other comparison tests I can run to provide more data happy to do so. Since the wires are right next to each other in the plug I can pull them out, throw a fuse in them and then be back to factory wiring. Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 24, 2020 Share Posted February 24, 2020 Had a chance to hook the relay up yesterday. I am really liking the Bussman ssVEC. Made hooking it up a snap. I picked up a new motor since the old one did not survive the exploratory surgery to see if I could powder coat it. The new one I got was 4W7Z-19805-AA (MM-929). This also required a jumper wire: Motorcraft Fuel Pump Connector Wiring WT-56853 (4W7Z-14A411-B) Wasn't really happy with the jumper wire design as it mixes wire gauges but I guess the relay mod mitigates that concern on the hot side although not the ground* Since the jumper is nothing more than two connectors spliced together and it's all right beside the relay block, it was pretty straightforward to split the splice, add MP 280 female terminals and plug it in. Ideally it would be in the grey plug since the jumper wire was pretty short but the ssVEC is split between two inputs (I am using one for the main battery and one for the aux) and the way I have it wired, the grey is aux powered. Here you can see the jumper wire connecting to the factory plug (white to black connector) and how I split it to go into the ssVEC. Sorry, lighting isn't the greatest. As Gary mentioned, I took some videos to try and show the sound difference between the two. Factory: Relay: If you keep both videos paused, set the factory one to 19sec and the relay one to 14sec, then play them one at a time right after each other you can hear the difference. If there are any other comparison tests I can run to provide more data happy to do so. Since the wires are right next to each other in the plug I can pull them out, throw a fuse in them and then be back to factory wiring. Looks great, Scott. As for the fan noises, I tried to quantify them by using the NIOSH SLM app on my phone and cranking the volume up. There was a bit of a problem getting things to settle before you moved to another speed, and announced it, on the lower speeds. So those don't quite match up as they should. But you left it on high long enough in both case that I could capture it. Stock Relay 1: 55 58 2: 63 65 3: 70 70 4: 72 76 Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Share Posted July 31, 2020 Looks great, Scott. As for the fan noises, I tried to quantify them by using the NIOSH SLM app on my phone and cranking the volume up. There was a bit of a problem getting things to settle before you moved to another speed, and announced it, on the lower speeds. So those don't quite match up as they should. But you left it on high long enough in both case that I could capture it. Stock Relay 1: 55 58 2: 63 65 3: 70 70 4: 72 76 Your fan without the relay sounds waaaay louder than mine. Did you have it on recirc? It's hard to tell from a recording though. My fan works on all speeds but it just seems to be wimpy all around. I suppose I should check for a voltage drop. If the motor works at all I can't imagine it not working all the way unless the bearing is dragging without making any suspicious noises. Mark Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Share Posted July 31, 2020 I was thinking he could check the ground at C603 back to the battery post. Obviously the relay should provide essentially no voltage drop, but since the stock wiring provides the ground back through the blower motor switch I expect some voltage drop. But Scott has some videos for us of before and after that he plans to post, so let's see what they sound like. Is this mod documented elsewhere on the site? Which model Bussman SsVec? Marki Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Share Posted July 31, 2020 Had a chance to hook the relay up yesterday. I am really liking the Bussman ssVEC. Made hooking it up a snap. I picked up a new motor since the old one did not survive the exploratory surgery to see if I could powder coat it. The new one I got was 4W7Z-19805-AA (MM-929). This also required a jumper wire: Motorcraft Fuel Pump Connector Wiring WT-56853 (4W7Z-14A411-B) Wasn't really happy with the jumper wire design as it mixes wire gauges but I guess the relay mod mitigates that concern on the hot side although not the ground* Since the jumper is nothing more than two connectors spliced together and it's all right beside the relay block, it was pretty straightforward to split the splice, add MP 280 female terminals and plug it in. Ideally it would be in the grey plug since the jumper wire was pretty short but the ssVEC is split between two inputs (I am using one for the main battery and one for the aux) and the way I have it wired, the grey is aux powered. Here you can see the jumper wire connecting to the factory plug (white to black connector) and how I split it to go into the ssVEC. Sorry, lighting isn't the greatest. As Gary mentioned, I took some videos to try and show the sound difference between the two. Factory: Relay: If you keep both videos paused, set the factory one to 19sec and the relay one to 14sec, then play them one at a time right after each other you can hear the difference. If there are any other comparison tests I can run to provide more data happy to do so. Since the wires are right next to each other in the plug I can pull them out, throw a fuse in them and then be back to factory wiring. You said in the original thread that you've put a relay on the hot side too. I assume it's for high only too, yes? Mark Link to comment Share on other sites More sharing options...
kramttocs Posted July 31, 2020 Share Posted July 31, 2020 Your fan without the relay sounds waaaay louder than mine. Did you have it on recirc? It's hard to tell from a recording though. My fan works on all speeds but it just seems to be wimpy all around. I suppose I should check for a voltage drop. If the motor works at all I can't imagine it not working all the way unless the bearing is dragging without making any suspicious noises. Mark Yeah, the recording isn't the most scientific approach for sure It made enough of a difference that I'd do it again in a heartbeat. Looking forward to seeing if the ground relay makes more of a difference. It looks like I had it in Normal AC. Didn't have any vacuum or ac hooked up though. The ssvec I am using is the 000 model. I have some more info in my Camano thread but if anyone is wanting to add multiple relays it's a great option. I spoke to the Bussman engineer that designed them a couple months ago and there is an 004 model that I think would be even more flexible in a lot of installs. None of the retailers stock that model yet although I've been contacting them every couple weeks. Link to comment Share on other sites More sharing options...
kramttocs Posted July 31, 2020 Share Posted July 31, 2020 You said in the original thread that you've put a relay on the hot side too. I assume it's for high only too, yes? Mark Well, let's say it makes the real impact in High. It comes into play with all levels but since the other levels aren't getting full voltage then it doesn't have the same impact. Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Share Posted July 31, 2020 Scott - I'm going to jump in as I think I know why, but want to see if my understanding is correct. I believe it is because the motor will act as a generator when the power turning it taken away, so current will be fed back into the truck via the relay's contacts. And as those contacts open the arc created by the current doing its best to flow can weld the contacts together. So this diode is in series with the contacts such that current can flow TO the motor but not FROM the motor. If that is correct then the diode has to be a rather substantial one as it has to be big enough to handle the full current of the motor for extended periods. (That's as opposed to the snubber diodes that just have to carry current very briefly as an inductor discharges.) Bill - Is that correct? God I hate it when motors have the TEMERITY to become generators and eff everything up. A big-ass diode oughta put them in their place. Mark Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Share Posted July 31, 2020 Well, let's say it makes the real impact in High. It comes into play with all levels but since the other levels aren't getting full voltage then it doesn't have the same impact. HIGH is all that matters. *cough cough* A relay on hot and ground with a diode should do it, yes? Mark Link to comment Share on other sites More sharing options...
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