Gary Lewis Posted January 20 Author Share Posted January 20 No It would be entirely separate from any schematic. Just a page by itself with graphic proportional representation of the PDC and a legend at the side/bottom defining each component Just like my Ford fuse box cover. Is this what you have in mind? It is what is in the EFI/driver's side PDB. I took a pic of the PDB and drew it up on CAD. And this is exactly what I need to do on the passenger's side PDB. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 20 Share Posted January 20 Is this what you have in mind? It is what is in the EFI/driver's side PDB. I took a pic of the PDB and drew it up on CAD. And this is exactly what I need to do on the passenger's side PDB. What does the inside of an 80-86 fuse box cover look like? Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 20 Author Share Posted January 20 What does the inside of an 80-86 fuse box cover look like? There's nothing on the inside of the cover, but there is on the outside. Here's what the cover from Dad's truck looks like: And here's what the cover on Big Blue looks like, and then there's a sheet in the documentation in the truck that shows which fuse serves what function and its current rating. But it would be a lot better if I were to put the ratings and usage on the fuse box cover also. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 20 Share Posted January 20 There's nothing on the inside of the cover, but there is on the outside. Here's what the cover from Dad's truck looks like: And here's what the cover on Big Blue looks like, and then there's a sheet in the documentation in the truck that shows which fuse serves what function and its current rating. But it would be a lot better if I were to put the ratings and usage on the fuse box cover also. Here's what the cover of my '87 looks like. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 20 Author Share Posted January 20 Here's what the cover of my '87 looks like. Obviously they hired someone with some reason. That's a much-improved cover. Now for some strange news. I've been using my DVMs to test voltages to the blower ground relay, the one that was obviously not working properly when I started this quest. The schematic is below and here are the results of my testing on each pin of the relay: 85: Gets key-on power, as planned 30: It has a great ground 87: Goes to the blower motor as expected. However it does have ~2 ohms resistance to ground with the relay out, which is what I measure on another resistor pack I have, so this must be correct. 86: This has from 2 to 6 ohms of resistance to ground depending on how you push on the handle of the blower speed switch. So obviously the switch itself is suspect, although that won't matter with the relay working as it'll be good enough to pull the relay in. HOWEVER, when I closed the door and the dome lights, all LED, went off the resistance dropped to .9 ohm from 2.2 ohms. So I'm trying to think through what would cause the reading to change that much. I'm thinking that it is a voltage differential between the ground in the cab, G701, and the ground at the battery, which is where my DVM was connected. But I cannot detect the difference, and my meters read to .001v. Having said that, it doesn't take much change in resistance testing to make a big difference. Maybe that's a red herring and I should stick to the ground relay issue. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 20 Author Share Posted January 20 Obviously they hired someone with some reason. That's a much-improved cover. Now for some strange news. I've been using my DVMs to test voltages to the blower ground relay, the one that was obviously not working properly when I started this quest. The schematic is below and here are the results of my testing on each pin of the relay: 85: Gets key-on power, as planned 30: It has a great ground 87: Goes to the blower motor as expected. However it does have ~2 ohms resistance to ground with the relay out, which is what I measure on another resistor pack I have, so this must be correct. 86: This has from 2 to 6 ohms of resistance to ground depending on how you push on the handle of the blower speed switch. So obviously the switch itself is suspect, although that won't matter with the relay working as it'll be good enough to pull the relay in. HOWEVER, when I closed the door and the dome lights, all LED, went off the resistance dropped to .9 ohm from 2.2 ohms. So I'm trying to think through what would cause the reading to change that much. I'm thinking that it is a voltage differential between the ground in the cab, G701, and the ground at the battery, which is where my DVM was connected. But I cannot detect the difference, and my meters read to .001v. Having said that, it doesn't take much change in resistance testing to make a big difference. Maybe that's a red herring and I should stick to the ground relay issue. More testing shows that with the blower ground relay working properly I have another conundrum - I'm getting different voltage drops across different relays when the blower is on high: Motorcraft: Tried two different ones and I get .31 to .35 volt Hella: Have one of these and I tested it several times - and got .70 to .73v Tyco: Have several of these and got .37 - .38 volt drop consistently ?: I have two relays with no names on them, and I got .40 - .42 volt drop across them Looks like I'll use Motorcraft relays. Next up is the blower power relay. But that may not be for a couple of days. Lots of church activities, as well as the Chief's game, tomorrow. Maybe Monday, although I have a Medicare "wellness" checkup that morning. But the forecast says we are going to have moisture and the temp will be right at 32, so the prognostications vary regarding the solidity of the moisture when it comes down. Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 21 Share Posted January 21 More testing shows that with the blower ground relay working properly I have another conundrum - I'm getting different voltage drops across different relays when the blower is on high: Motorcraft: Tried two different ones and I get .31 to .35 volt Hella: Have one of these and I tested it several times - and got .70 to .73v Tyco: Have several of these and got .37 - .38 volt drop consistently ?: I have two relays with no names on them, and I got .40 - .42 volt drop across them Looks like I'll use Motorcraft relays. Next up is the blower power relay. But that may not be for a couple of days. Lots of church activities, as well as the Chief's game, tomorrow. Maybe Monday, although I have a Medicare "wellness" checkup that morning. But the forecast says we are going to have moisture and the temp will be right at 32, so the prognostications vary regarding the solidity of the moisture when it comes down. How many different relays would you like for testing? Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 21 Author Share Posted January 21 How many different relays would you like for testing? I think I'm done testing. Wish I could get that HD Bosch relay in but the bigger terminal won't go. However, I could cut that terminal down. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 21 Share Posted January 21 I think I'm done testing. Wish I could get that HD Bosch relay in but the bigger terminal won't go. However, I could cut that terminal down. Have a look at the massive relay selection from Texas Industrial Electric https://www.texasindustrialelectric.com/relays.asp Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 21 Author Share Posted January 21 Have a look at the massive relay selection from Texas Industrial Electric https://www.texasindustrialelectric.com/relays.asp Thanks, Jim. I'm blown away with the number of listings they have. I found the ones shown at the bottom of the post and got excited as they are supposedly 50A versions and don't appear to have the larger terminal typical of those relays. But then I Googled "0 332 019 103" and found this listing on Amazon which says it is a 30A relay. However, we know that Amazon frequently has incorrect descriptions, so I found this Bosch relay catalog and, sure enough, that is a 30A relay - with a mounting tab no less. However, the Bosch catalog shows a 0 332 019 109 and says it is a 50A relay. But Pelican Parts carries that relay and their picture clearly shows the part number and that it is rated at 30A. What am I missing? Link to comment Share on other sites More sharing options...
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