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sprinkles08, Chrysler/Dodge/Jeep master tech
Category: Dodge
Satisfied Customers: 23129
Experience:  ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans and Hybrid Specialist
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I have a 1985 Dodge truck its been sitting while. It

Customer Question

I have a 1985 Dodge truck its been sitting for a while. It completely dies when I apply the brakes. I had it checked out and replaced the brake booster with one from a junk yard, same problem. I replaced the alternator because it kept running the battery down and dying and it turned out it was a bad voltage regulator so we replaced it with new one now its putting out plenty of amps but seems to drive fine unless I apply the brakes and the lights go dim and it dies.
JA: Battery issues can be tough to diagnose - lots of things to consider. Luckily, the mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: yes
JA: Great! What have you tried so far?
Customer: replaced the brake booster (used)?, plugs, distributer, voltage regulator, fuel pump, alternator. the brake light stays on turn signals don't work, I am not as concerned with that I will trouble shoot that and fix, but the issue I am trying to solve is the engine stalls when applying the brakes.
JA: Is there anything else the Dodge Mechanic should be aware of about your Dodge?
Customer: its been sitting for about 5 years on our farm, mice could have caused problems but the mechanic could not find any wiring issues other than the voltage regulator being bad. all the rest I did because it was sitting so long.
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Dodge Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Dodge
Expert:  Master Auto Tech. replied 1 year ago.
Hi, I am sorry you are having a problem with your dodge, I will see if I can help out with this problem. It's definatly an interesting one. We first will need to see if the problem is mechanical or electrical. Try taking the vacuum hose that runs to the brake boost and blocking it off. Whether you unhook it and put a plug in it or just clamp it tight with needle nose vise grips with black tape on the jaws doesn't matter. (Just don't clamp to tight, tight enough to completely block it off but not so tight that you ruin the hose) then see if it dies when you apply the brake.
Expert:  Master Auto Tech. replied 1 year ago.
If it does then disconnect the wire from the brake switch on the brake pedal. And retry and see if it dies.Try one or both of these suggestions and let me know what happens and I will guide you further.Thanks
Customer: replied 1 year ago.
I do not have the truck here, I will have to go to my daughters hose to try your suggestion.
Customer: replied 1 year ago.
daughters house,
Expert:  Master Auto Tech. replied 1 year ago.
Ok no problem. Just let me know when you have. I sign on every day so if I'm not on when you reply I will see it when I get back on.
Customer: replied 1 year ago.
Ok sorry for the delay, I disconnected the main vacume hose to the brake booster and plugged it with a bolt to cut off the air flow therefore separating the brake booster system. I pushed the brake down and all the interior lights went dim and engine died. If the head lights are on and I hit it brakes it immedietly kills the engine. Even when the engine is NOT running if I hit the brake pedal all lights go dim. as if its a kill switch. the brake light stays lit when running. it goes off when the brake pedl is depressed kinda reverse of what t should do. I unhooked the wires going to the brake switch on the pedal it still dies when the brake s depressed, with the brake booster connected. I didn't unhook the brake switch with the bake booster disconnected to see if it has an effect. t definately has a wiring issue with the brake. I am very perplexed. the mechanic tried to figure it out and replaced the voltage regulator because the battery kept draining and would die if the battery terminal was disconnected. I hooked a voltage meter up. Its putting out 19-20 volts with the battery positive cable disconnected and when you depress the brake drops to 16-17 volts.
Expert:  Master Auto Tech. replied 1 year ago.
Oh wow. That's tuff. I'm sorry but it sounds like it has several issues, probably caused by those pesky rodents. I don't think I'd be able to help you unless I was there testing it. Sorry I think I'm going to have to opt out.
Expert:  sprinkles08 replied 1 year ago.
Hello and welcome to JustAnswer!It sounds like you have a couple issues going on. If the engine still dies with the brake switch wiring disconnected when the pedal is pressed then you do have a booster issue, but that obviously wouldn't cause the engine to die when pressing the brake while the booster vacuum is disconnected.A battery cable should never be disconnected with the engine running as it will cause charging voltage to spike high as you've seen, and can instantly damage any electrical component.With the battery cables connected and engine idling what is the voltage seen across the battery posts (not the terminals)?