ckuske Posted May 8 Share Posted May 8 I've moved onto my next item: Speed Control not working It was non-operational when I bought the truck back (meaning it never engages/turns on) I've printed out the FSM section, and have started to run tests. I'm at Page 37-01-3 of the FSM. The first test (Test for 12 Volts when On Button Pressed) is passing. But, that's where my luck ends. Step 2 of checking for 0-1 Ohms when pressing the OFF button is failing. When my steering wheel is locked, it seems like the circuit is open. If I put the truck in Run and the steering wheel unlocks, I get a 100-200 Ohms. If I turn the wheel about 1/4 turn, the ohms go down to 40-60, but certainly never to 0-1 Ohms. I'm guessing the back side of the steering wheel isn't making good contact with the brushes on the turn signal switch? The horn is working in different wheel positions, that's never been a problem. Besides checking the brushes (the turn signal switch is brand new, put it about a year ago with very little use), what else should I be looking at if turning the wheel seems to alter the resistance readings? Link to comment Share on other sites More sharing options...
ckuske Posted May 8 Author Share Posted May 8 Here are a few pictures of the steering wheel and the turn signal switch: Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 8 Share Posted May 8 It seems like you have a grounding problem. Can you show us a pic of the way your steering wheel is wired? Link to comment Share on other sites More sharing options...
ckuske Posted May 8 Author Share Posted May 8 It seems like you have a grounding problem. Can you show us a pic of the way your steering wheel is wired? Sure thing - the yellow and blue wires go onto the two ears inside the steering wheel, and the ground wire fits inside one of the bolt holes that are used to pull the wheel. It seems that is normal after doing some reading - it seemed questionable at first... Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 8 Share Posted May 8 Sure thing - the yellow and blue wires go onto the two ears inside the steering wheel, and the ground wire fits inside one of the bolt holes that are used to pull the wheel. It seems that is normal after doing some reading - it seemed questionable at first... Yes, that is normal. But if the ground isn't good you'll have lots of odd problems. Big Blue's horn worked with the key off but not on at one point. Turned out that the speed control was working as the ground for the circuit until it was powered up, but then it wasn't a good enough ground to pull in the relay. I don't remember what the problem was, but I know others have had problems where the steering column wasn't well grounded. And that's where I'd recommend you start. Measure from the column to ground and move the wheel around, as you've done. If it changes then you aren't well grounded. Link to comment Share on other sites More sharing options...
ckuske Posted May 8 Author Share Posted May 8 Yes, that is normal. But if the ground isn't good you'll have lots of odd problems. Big Blue's horn worked with the key off but not on at one point. Turned out that the speed control was working as the ground for the circuit until it was powered up, but then it wasn't a good enough ground to pull in the relay. I don't remember what the problem was, but I know others have had problems where the steering column wasn't well grounded. And that's where I'd recommend you start. Measure from the column to ground and move the wheel around, as you've done. If it changes then you aren't well grounded. I measured ground from the metal collar on the column (right below the wheel) to a dash attachment point, and it came out to zero ohms. Like 0.0 ohms which I thought was kind of suspicious - should I not use the dash mounting legs as the other end of the ground test? The test said to pick body sheet metal - maybe I take a kick panel off and try there are the ground point? If all that is OK though, I'm assuming in general the column is grounded but the continuity from the wheel through the column is bad. Should I pick one of the connection points (aka "ears") on the wheel as one end of this continuity test? (Where the blue/yellow wires attach) Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 8 Share Posted May 8 I measured ground from the metal collar on the column (right below the wheel) to a dash attachment point, and it came out to zero ohms. Like 0.0 ohms which I thought was kind of suspicious - should I not use the dash mounting legs as the other end of the ground test? The test said to pick body sheet metal - maybe I take a kick panel off and try there are the ground point? If all that is OK though, I'm assuming in general the column is grounded but the continuity from the wheel through the column is bad. Should I pick one of the connection points (aka "ears") on the wheel as one end of this continuity test? (Where the blue/yellow wires attach) The only grounding point that really matters to the speed control is where it is grounded. And according to the schematic that is G703, which is said to be "attached to brace under steering column". It is depicted on Page 139 in illustration #2. So I'd check out that ground and do my test from the steering column's flange where your ground clip goes in to G703. There shouldn't be any bobbles when you move the wheel, pull on it, turn it, etc. But, G703 should also have a good connection to the body, so check that out as well. One spot I frequently use is the bracket for the dash just above the emergency brake. But you may have a grounding problem to the cab. There's supposed to be a ground from the engine to the firewall near the windshield wiper motor. Link to comment Share on other sites More sharing options...
ckuske Posted May 9 Author Share Posted May 9 The only grounding point that really matters to the speed control is where it is grounded. And according to the schematic that is G703, which is said to be "attached to brace under steering column". It is depicted on Page 139 in illustration #2. So I'd check out that ground and do my test from the steering column's flange where your ground clip goes in to G703. There shouldn't be any bobbles when you move the wheel, pull on it, turn it, etc. But, G703 should also have a good connection to the body, so check that out as well. One spot I frequently use is the bracket for the dash just above the emergency brake. But you may have a grounding problem to the cab. There's supposed to be a ground from the engine to the firewall near the windshield wiper motor. Found G703. Another ground I never knew existed, because I never took the ECU or Speed Control Amplifier out of the truck even though I stripped the rest of the interior awhile back. I will try to do some tests tomorrow against this ground, but it looks good. I tweaked my back a few days ago and even though I am motivated to test all these connections, lying on my back over the transmission hump upside down doesn't feel so great that the moment! I had some choice words when I was trying to get the connections off the amplifier... PS - I no idea what that three terminal connector is for. It must not be used in my truck? Â Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 9 Share Posted May 9 Found G703. Another ground I never knew existed, because I never took the ECU or Speed Control Amplifier out of the truck even though I stripped the rest of the interior awhile back. I will try to do some tests tomorrow against this ground, but it looks good. I tweaked my back a few days ago and even though I am motivated to test all these connections, lying on my back over the transmission hump upside down doesn't feel so great that the moment! I had some choice words when I was trying to get the connections off the amplifier... PS - I no idea what that three terminal connector is for. It must not be used in my truck? I don't know that I would say it looks good. The bracket the eyelet is going down against is painted, so you may not have a ground. And if it really is connected to the bracket is the bracket connected to the firewall? And is the firewall connected to the engine? Ford was very lax with grounds up through '86. In '87 and later they started adding a lot of grounds. So our trucks aren't grounded well and there's no redundancy. If one of those grounds isn't working then lots of problems arise. As for the back, that sounds painful! Hope you get some relief. Link to comment Share on other sites More sharing options...
ckuske Posted May 9 Author Share Posted May 9 I don't know that I would say it looks good. The bracket the eyelet is going down against is painted, so you may not have a ground. And if it really is connected to the bracket is the bracket connected to the firewall? And is the firewall connected to the engine? Ford was very lax with grounds up through '86. In '87 and later they started adding a lot of grounds. So our trucks aren't grounded well and there's no redundancy. If one of those grounds isn't working then lots of problems arise. As for the back, that sounds painful! Hope you get some relief. True about the paint - I was just happy I was able to find it! If anyone else has a picture, I'd be curious to see what theirs looks like. I'm pretty confident things are good with the grounds to the engine. I know for sure the EEC has a ground to a post on the intake that I redid. I'll try to trace this one back and see if it's part of the same harness coming through the firewall or is something different. My back is better each day, once every couple years I get spasms that lock up my lower back and after a few days the muscles relax and I'm back to normal. It could be worse! Maybe I'll try to relocate that ground - or even jumper it to somewhere else as a test? I still think there is a problem when turning the wheel that is separate. The ohms shouldn't jump around from just turning the wheel. The copper contacts on the switch look a little worn, but I'm assuming since the back of the wheel rubs on that, it's normal? Perhaps I should use fine grit sandpaper and sand the disc on the back of the steering wheel? I'm probably getting ahead of myself - one thing at a time. But I'm trying to anticipate my next move... Link to comment Share on other sites More sharing options...
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