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Car Forum / Chrysler Cars / September 2004'90 New Yorker Hot under the Ignition Switch
Hi all! My '90 New Yorker, 3.3L, has a problem that has me stumped. Whenever I drive the car, and the a/c heater blower is running, the plastic cover under the ignition switch gets very hot to the touch to the point that the plactic has cracked. I have also had to replace the ignition switch three times in the last three years. This car has ATC. I am thinking that either the ATC or the blower is drawing too much current, but how can I tell which? Or could there be some other cause? THanks in advance for reading, and for any advice. Dennis sedNOSPAMMERS55atyahoo.NOSPAMMERS.com (remove NOSPAMMERS and convert at to @) > Hi all! > [quoted text clipped - 12 lines] > sedNOSPAMMERS55atyahoo.NOSPAMMERS.com > (remove NOSPAMMERS and convert at to @) I was hoping someone would have responded to this. I had a similar problem with a 1968 Dodge Dart many years ago. When the A/C was run on a daily basis, the A/C/heat/defroster switch would get hot and melt. We replaced it several times. There was one time, when all of the solder in the fuse melted and dripped on the floor. (The correct fuse was being used.) The fuse never "blew" like they normally do. All I can figure is that the blower must have been drawing too much current. The problem was never solved, and the car was traded in a year later. I wished that I would have had a way to measure the current going through the blower. I could not imagine that the A/C compressor clutch could have been doing it. -Kirk Matheson > I was hoping someone would have responded to this. I had a similar > problem with a 1968 Dodge Dart many years ago. When the A/C was run on a > daily basis, the A/C/heat/defroster switch would get hot and melt. That is because the switch was very heavily loaded even when all the wires and components were in perfect shape. ALL the current to operate the blower motor and compressor clutch went through that switch. Let a couple of adjacent clutch coil windings short together, let the blower motor draw a little too much current, and that switch was gonna melt, every time. > I wished that I would have had a way to measure the current going > through the blower. Very easy. Both wires were readily accessible from the engine side of the firewall. > I could not imagine that the A/C compressor clutch could have been doing > it. How come? The 6-cylinder models had higher-current-draw coils (wound with aluminum wire rather than copper like the 8-cylinder models had) and even with *no* adjacent coils shorted, those clutches drew a great deal of current. >>I was hoping someone would have responded to this. I had a similar >>problem with a 1968 Dodge Dart many years ago. When the A/C was run on a [quoted text clipped - 5 lines] > of adjacent clutch coil windings short together, let the blower motor draw > a little too much current, and that switch was gonna melt, every time. Couldn't they have just used a relay? They had relays back in 68... Ray > >>I was hoping someone would have responded to this. I had a similar > >>problem with a 1968 Dodge Dart many years ago. When the A/C was run on a [quoted text clipped - 9 lines] > > Ray With the manufacturing techniques of the day (compare the cost of making an existing wire one foot longer vs. replacing that one foot with a relay and at least four terminations - terminal on the end of each of four wires, and connecting each of those terminals either with screws or with push-on friction connections), relays added too much expense and complexity to the vehicle cost. Also, relays add some current draw in addition to the load it is switching, which also was a consideration to an already overtaxed (for the day) charging system. Today's lower component costs (in adjusted dollars) using near slave labor and automated mass termination methods make it feasible, and, with the total system loads, necesary, to use servo (electro-mechanical, solid state switching) devices rather than full current-carrying controls. Weight may also be reduced by running much smaller control wires around the barn, so to speak, to low-current controls and switches rather than the full current-carrying wires along the same labyrinthine paths to much heftier switches (or, for more weight reduction, multiplexing buses, integrated circuits, and microprocessors). Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x") >>>>I was hoping someone would have responded to this. I had a similar >>>>problem with a 1968 Dodge Dart many years ago. When the A/C was run on a [quoted text clipped - 27 lines] > heftier switches (or, for more weight reduction, multiplexing buses, > integrated circuits, and microprocessors). I suspect that cost (both parts and added assembly time) was the reason. The extra current draw (power consumption) of the control coil of a relay is pretty small and I suspect probably no greater than the extra power required to overcome the IsquaredR losses of the extra wire required to run these loads through the switch. Relays are the way to go, but I'm still not convinced about having the BCC controlling the relays. There is a noticeable lag in my 03 Caravan between changing from high to low beam and the lights actually responding. My 96 is instantaneous from the level of human perception, but my 03 has a noticeable lag. It is probably less than 500 ms, but very noticeable nonetheless. I don't have a schematic for my 03, but I'm guessing this is due to moving this control the the computer to save some wiring. Matt > Relays are the way to go, but I'm still not convinced about having the > BCC controlling the relays. There is a noticeable lag in my 03 Caravan > between changing from high to low beam and the lights actually > responding. I *detest* these kinds of delays, and I have found them in virtually every BCC-equipped car I've driven since the mid 1990s. Turn the key to "Start", turn the headlamp switch on, change the headlamp beam, turn the ignition key to "off", hit a power window switch...and there's a brief but perceptible delay before anything happens. >>Relays are the way to go, but I'm still not convinced about having the >>BCC controlling the relays. There is a noticeable lag in my 03 Caravan [quoted text clipped - 6 lines] > key to "off", hit a power window switch...and there's a brief but > perceptible delay before anything happens. Likewise. I just don't see the advantage and the delay is annoying to say the least. Matt > Relays are the way to go, but I'm still not convinced about having the > BCC controlling the relays. There is a noticeable lag in my 03 Caravan [quoted text clipped - 6 lines] > > Matt Boy, I'll second that! The delay in our '03 GC is significant--enough that I'm not always sure the high beams flash when I'm using them to signal somebody that it's okay to move into the lane in front of me. It can and should be a much faster mechanism. --Geoff > > > That is because the switch was very heavily loaded even when all the > > > wires and components were in perfect shape. ALL the current to > > > operate the blower motor and compressor clutch went through that > > > switch. Let a couple of adjacent clutch coil windings short > > > together, let the blower motor draw a little too much current, and > > > that switch was gonna melt, every time. > > Couldn't they have just used a relay? They had relays back in 68... > With the manufacturing techniques of the day (compare the cost of making > an existing wire one foot longer vs. replacing that one foot with a > relay and at least four terminations - terminal on the end of each of > four wires, and connecting each of those terminals either with screws or > with push-on friction connections), relays added too much expense and > complexity to the vehicle cost. Yes, so the beancounters figured. > Also, relays add some current draw Negligible, insignificant. This is not a consideration factor. > an already overtaxed (for the day) charging system. Nope. The charging systems in Darts and Valiants were completely adequate. > Today's lower component costs (in adjusted dollars) using near slave > labor and automated mass termination methods make it feasible, and, with > the total system loads, necesary, to use servo (electro-mechanical, > solid state switching) devices rather than full current-carrying > controls. Naw, the extra cost is still there, it's just taken back out by using bare-minimum wire gauge in the load circuits. They work OK when everything's brand new and clean, and will tolerate juuuuuuuust enough deterioration to get the vehicle to the point of warranty expiry. >>>>I was hoping someone would have responded to this. I had a similar >>>>problem with a 1968 Dodge Dart many years ago. When the A/C was run on a [quoted text clipped - 35 lines] > http://www.newsfeeds.com - The #1 Newsgroup Service in the World! > -----== Over 100,000 Newsgroups - 19 Different Servers! =----- You coulda just said Chrysler was cheap. ;) Trust me, I'm well aware of the car companies neverending drive to save $2 on manufacturing costs per car in exchange for serviceability nightmares... but in their defense, $1 per device x 50 devices per car x 500,000 cars is a lot of money... Ray Is there a way I can measure the current being drawn by the blower in my Chrysler? Should I just replace the blower motor? I assume by reading the feedback that the blower motor is the culprit here since the situation occurs whether you're using A/C or heat. Thanks! > > I was hoping someone would have responded to this. I had a similar > > problem with a 1968 Dodge Dart many years ago. When the A/C was run on a [quoted text clipped - 19 lines] > even with *no* adjacent coils shorted, those clutches drew a great deal of > current. > Is there a way I can measure the current being drawn by the blower in my > Chrysler? Same way you measure the current being drawn through any circuit -- with a properly-applied ammeter. > Should I just replace the blower motor? No, you should properly diagnose the problem. Throwing parts at the problem is a real shot in the dark. |
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