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Ignition solenoid testing


Jim Bob

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so, I read a couple other threads that indicated an intermittent lack of dash fans, cruise control, dash lights, step retraction, etc. might be a bad ignition solenoid located in the FRB.  So, short of replacing it, is there a way to test the solenoid?  As in jumping from one side to another to see if the dash fans work? Also, all the 12v lights in the basement do not work.  I have no idea if these are related as I rarely used the lights and when one didn't work, I assumed it was a bulb that needed to be replaced.  When I finally got around to checking bulbs, I figured out that none of them worked, but no idea if the timing was the same as the lack of dash fans.  Again, the dash fans are not something I used very often.  I've checked the fuses and they are good.  To replace the solenoid, remove it and find a part number?  Is it likely a local auto parts store will have it? 

Thanks a bunch. 

Jim

95 Dynasty. 

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Upon further review... It appears that the dash fans, compartment lights and step are all on this upper block with the large black wire coming in and looping down to the bottom.  This particular electrical block appears to be wired opposite of the other blocks in the FRB as all the others have a large red wire coming in.  So, it would appear to my limited electrical mind that the small wires are the positive side and the large black wire is the negative?  If so, where do the small wires get their power?  I would assume that all those circuits are not switched with the ignition and are powered somewhere else, so any suggestions where to look for that power source? 

close up.jpg

fuse layout.jpg

whole thing.jpg

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Well I’m about like you. DC throws me. Give me 480-600 AC. Anyway if that red wire( +) were to be removed, I wonder ir that is your power source and the black is the negative. Hopefully someone smarter than me will help.

Edited by Gary M
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Well if it was me, the 1st thing i would do is to remove the little wires that are coroded, reconnect them then retighten all the connections, as for the bigger lugs i would loosen then retorque them to 45 in lbs.

i would want to see how those big lugs are powered upstream, either by direct bsttery connection or power solinoids an clean an tighten those connections, ya gotta figure a rig with that many happy miles just may be needing some love. Then i would use my test light and test those circuits for correct integrity, positive is positive and ground is ground ( to do this i use a “smart” test light, has made my work sooooo much easier and timely) lastly i would be giving a big eye towards the ignition switch, the one that come to mind for me are the GM styles, i was having a problem with my DP starting, it would crank just fine, i would darn near run my batteries dead before it would start, i decided to replace the switch first BEFORE i did any diag, once i replaced it DONE it starts first time every time. That was a year ago, now every now an then some of my accessories will not operate until i wiggle the key just a little an then everything works. So i ordered an carry another switch with me.

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When my dash fans and power shades quit working, I checked fuses which were all good then tested the ignition solenoid and with the ignition on power was going in but no power coming out so I removed the solenoid and replaced with the same part number from my local NAPA store. Problems solved in my case.  Also I have done as Rik W suggested about tightening connections.  Good luck!

Edited by StephenW
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Looks to me that you have 2 sources of +12V (one red & one black) power to the 3 boards… the grounds are at the items. Not sure why the jumper was added from the red +12V to the 15A clearance lights fuse… surprised your clearance lights work and those connections need cleaning.

Edited by Ivylog
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I agree with Ivylog, that black wire is likely a +12 VDC jumper (don't know why) and NOT a ground.  It would be easy to determine, check the voltage between the two, and then between each one and a known ground.  The closest wiring diagram I have is for a 97 Dynasty.  It is wired differently.  The house battery (called "Domestic") has the Spotlight, Dash Fans, 12V Outlets, CB, Front (& Rear if applicable) Radios, Hood Light, Bay Lights, and Step.  Those would work whenever you have the House Battery turned on.  Then it has "Chassis" terminal strip that is connected to the Chassis battery.  That operates Security System, Security Siren, Clearance Lights, Docking Lights, Radio Memory, Horn, Brakes, Running Lights, ABS, and Hazard lights.  Lastly, there is the "Ignition" Terminal Strip.  This is active only when the ignition is turned on which energizes the Ignition Relay (solenoid) you asked about.  It supplies power to the Backup lights, Mirror heat, Wipers, Gauges, Air Dump, Step Ignition (to move the step in/out when ignition is turned on), Security System Optional, Dash A/C, TV (Inhibit TV when ignition is on), Levelers, Mirrors, Cruise, Air Dryer, Driving/Fog Lights, Eng Brake, Fuel, and ABS for Ignition.  I know this is different than your 95 Dynasty (do you have a wiring diagram for the Front Run Bay?) but maybe the theory of how things were wired will help.  If you wanted to jump the Ignition Relay, it is likely located at the end of that Large Red cable.  There should be another large cable going to the Ignition Relay, along with two much smaller wires.  Jump between the two large wires.  But do this only with the engine shut off, and for a short term test.  If the engine is running, you might not be able to shut off the engine since the fuel shut off will always be on.  

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Thanks so much for the replies.  Cleaning and making sure they were tight is on the list to do.  There is no power coming to the large looped around black wire, so I'll see if I can trace a source of where it is coming from.  The solenoid side seems to be working fine.  I'm thinking if the black wire is a positive, then I should be able to disconnect the black wire and jump a known good positive to that terminal to see if the dash fans, etc work?  I would at least know the direction I had to go to run down a break or blown fuse or something.... from the FRB back to the batteries.  Does that sound reasonable?

Ivy, I was curious about that positive jumper wire myself.  No idea why that is there, but that is how it came from the factory.  The clearance lights work, but they are not your normal lights.  That must be the interrupt switch so you can use the ICC switch on the dash to flash the lights???  Just a guess. 

Thanks again everyone.  

Jim

 

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small success.  I disconnected the black wire that comes in and jumped a positive and the basement lights and dash fans worked.  Now the bigger issue is I have no idea where that large black wire comes from.  I do not have battery disconnects and the other 12v house circuits work.  Any suggestions where I might look for a large black 12 v wire running from one end to the other?  It comes out of the top of the FRB, but cannot see anything looking down through the driver's left side controls (I can remove the cup holder and see a mess of wires but none of them are the size of the black one).  Any suggestions/guesses as to where that wire runs would be appreciated, I really have no idea where to even start to look.

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I would think that there would be few large fuses to protect the large gauge wires somewhere? Our high DC current box is beside the engine, it should be somewhere not too far from the batteries,  I would expect.

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Jim the schedule you provided points to the chassis battery.

I would replace everything in your photo. Current carrying metal components are plated, oftentimes with cadmium,  so as to inhibit corrosion from chemical and electrolytic processes. Abrasive cleaning can be expected to remove whatever is left of the coating. Terminal blocks are inexpensive and are available with LED's which indicate a blown fuse. The DC ground (negative battery terminal), the chassis, the AC grounded conductor (neutral), and the AC equipment grounding conductor are all bonded together at a single point per the NEC. In order to identify a DC ground or either of the 2 grounded AC circuits check for voltage from the conductor and the chassis or something bolted to it. 

Edited by Gary Cole
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I little more success.  I found some black wires in the back near the engine and batteries.  It appears the solenoid that goes to the "salesman switch" is the culprit.  I jumped a known positive wire to one of the black wires and have operable dash fans and basement compartment lights.  Now my question is...  can I eliminate that solenoid?  I really hate having that power switch up by the front door.  Whenever you are carrying something wide or your inadvertently hit the switch it kills all the power.  Just a PIA place to have that switch.  So, can I just tie all those power cables together on one post of some kind?  Other than not having a switch to turn off the power is there any other negative?  I currently don't have any kind of battery cut off back by the batteries.  Would installing a switch there be the same thing?  I can take pictures of that area if you need them.  Thanks again to everyone that has replied.  It is so helpful to have this group of people that can share their knowledge!!!

Jim

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Jim,

yes, you can tie them together by hooking them up on the same side of the solenoid. Pretty common practice to eliminate the salesman switch. A battery disconnect at the batteries will shut down all 12 volt functions, another common practice to isolate batteries when not in use. Hope this helps.

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