Gary Lewis Posted July 31, 2020 Share Posted July 31, 2020 I second the high speed blower relay mod. Was driving today with it on high and the kids in the backseat were complaining about the breeze. I will be interested if you find a condenser. I tried and never could find a direct fit that didn't require either enlarging the opening on the core support or tilting the bottom of the condenser out towards the grill. Ended up cleaning and keeping the stock one but wouldn't mind having a newer spare in case. Gary - did you not have to tilt yours? Just some advice but think about who you are ordering from and their return policy just in case it doesn't match the photos or description and doesn't fit like stated. I used the condenser from Huck, the 1990 half-truck, and the only mod I had to make was to move the support arm for the inlet on the passenger's side up just 1/4". Other than that it fit perfectly. And the angle on the bottom was "factory" as the brackets fit very nicely. Link to comment Share on other sites More sharing options...
grumpin Posted July 31, 2020 Share Posted July 31, 2020 I second the high speed blower relay mod. Was driving today with it on high and the kids in the backseat were complaining about the breeze. Not to hijack a thread, but I can’t wrap my head around this. High speed is going to ground. Why does this help? The EVTM shows the diesel only part, but the grounds page show it going to ground through G701. The diesel has a connector for some reason. Path of least resistance and all. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 31, 2020 Share Posted July 31, 2020 I second the high speed blower relay mod. Was driving today with it on high and the kids in the backseat were complaining about the breeze. Not to hijack a thread, but I can’t wrap my head around this. High speed is going to ground. Why does this help? The EVTM shows the diesel only part, but the grounds page show it going to ground through G701. The diesel has a connector for some reason. Path of least resistance and all. Dane - You have an excellent question! The wiring for the blower motor follows this path in High: Battery to ignition switch Ignition switch to Fuse 9 Fuse 9 to A/C Function Switch A/C Function Switch to motor Motor to Blower Speed Switch Blower Speed Switch to ground So, to summarize, the power flows from under the hood into the cab, back under the hood, and then back into the cab and to ground. What I did was to skip the run from the motor to the blower speed switch and take it directly to ground in my PDB via a relay. And, I'm sure that helped. But, what if for High we used a DP relay and fed the motor power from the PDB and grounded it then and there? We'd take out a whole bunch of wiring, connections, etc. I can probably easily do a voltage drop test to see how much drop there is 'tween the battery and the positive side of the motor in High. Then we'd know what kind of difference that would make. I'll do that in a few..... Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 31, 2020 Share Posted July 31, 2020 Dane - You have an excellent question! The wiring for the blower motor follows this path in High: Battery to ignition switch Ignition switch to Fuse 9 Fuse 9 to A/C Function Switch A/C Function Switch to motor Motor to Blower Speed Switch Blower Speed Switch to ground So, to summarize, the power flows from under the hood into the cab, back under the hood, and then back into the cab and to ground. What I did was to skip the run from the motor to the blower speed switch and take it directly to ground in my PDB via a relay. And, I'm sure that helped. But, what if for High we used a DP relay and fed the motor power from the PDB and grounded it then and there? We'd take out a whole bunch of wiring, connections, etc. I can probably easily do a voltage drop test to see how much drop there is 'tween the battery and the positive side of the motor in High. Then we'd know what kind of difference that would make. I'll do that in a few..... Well, with the engine off (it ain't running yet) the battery voltage was 12.83 volts, and the drop from the battery to the positive side of the blower motor on High was 2.03 volts. That's a 16% loss. Link to comment Share on other sites More sharing options...
grumpin Posted July 31, 2020 Share Posted July 31, 2020 Well, with the engine off (it ain't running yet) the battery voltage was 12.83 volts, and the drop from the battery to the positive side of the blower motor on High was 2.03 volts. That's a 16% loss. I was assuming it had to be wire size or distance. 16% loss, I also assume that’s with the relay set up. My next question is, why a relay? Couldn’t you just ground it near the blower motor? Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 31, 2020 Share Posted July 31, 2020 I was assuming it had to be wire size or distance. 16% loss, I also assume that’s with the relay set up. My next question is, why a relay? Couldn’t you just ground it near the blower motor? That is with a ground relay. Not power relay. As for ground near the blower motor, no. The wire goes back to the switch in the dash, and that switch has: No connection to let the power go through all of the resistors in series and then to ground, which gives Low A connection to go through two resistors and then to ground for M1 A connection to go through one resistor and then to ground for M2 A connection straight to ground for High. But that wire comes all the way back to the switch from the motor, so I put a relay in it to go to ground by the motor, but controlled by the speed switch's High position. Link to comment Share on other sites More sharing options...
grumpin Posted July 31, 2020 Share Posted July 31, 2020 That is with a ground relay. Not power relay. As for ground near the blower motor, no. The wire goes back to the switch in the dash, and that switch has: No connection to let the power go through all of the resistors in series and then to ground, which gives Low A connection to go through two resistors and then to ground for M1 A connection to go through one resistor and then to ground for M2 A connection straight to ground for High. But that wire comes all the way back to the switch from the motor, so I put a relay in it to go to ground by the motor, but controlled by the speed switch's High position. Ding! Light bulb finally appeared above my head! Thank you, now I have my head wrapped around it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 31, 2020 Share Posted July 31, 2020 Ding! Light bulb finally appeared above my head! Thank you, now I have my head wrapped around it. Let's see if this helps. Here's Gary's version of the wiring with relative positions shown. My ground relay replaces the orange wire. But a better approach would to be to replace all of the red wires with a relay, and there's where the 2.03 volt drop was measured. But the best approach would be to do both. I don't know where Scott put his relay. Maybe he will tell us. Link to comment Share on other sites More sharing options...
kramttocs Posted July 31, 2020 Share Posted July 31, 2020 Let's see if this helps. Here's Gary's version of the wiring with relative positions shown. My ground relay replaces the orange wire. But a better approach would to be to replace all of the red wires with a relay, and there's where the 2.03 volt drop was measured. But the best approach would be to do both. I don't know where Scott put his relay. Maybe he will tell us. Glad you brought this up Dane. I did the power side relay since I was working in that area and it is easy to implement. I plan on doing the ground side at some point to offload the blower switch. Bill has some good insight on this topic as well. Let's continue this here if ok with everyone. Link to comment Share on other sites More sharing options...
BullnoseLuvr Posted July 31, 2020 Author Share Posted July 31, 2020 I second the high speed blower relay mod. Was driving today with it on high and the kids in the backseat were complaining about the breeze. I will be interested if you find a condenser. I tried and never could find a direct fit that didn't require either enlarging the opening on the core support or tilting the bottom of the condenser out towards the grill. Ended up cleaning and keeping the stock one but wouldn't mind having a newer spare in case. Gary - did you not have to tilt yours? Just some advice but think about who you are ordering from and their return policy just in case it doesn't match the photos or description and doesn't fit like stated. I found a condensor at PepBoys. It's a crossflow type, but listed for the '84. I'm going to pull my original condensor and take it with me on Monday to compare with the new part and bring it home if it fits or is close enough that making it fit won't be a big deal. I'm going to take my new hoses with me to check the connections. My original is good and I could flush it but I'd feel better replacing every component and the condenser is the last one standing. Mark Link to comment Share on other sites More sharing options...
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