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Discussion Starter #1
I have an intermittent brake warning light issue for a few months now. Disconnected the emergency brake switch and tested; switch is good and light still comes on with it disconnected. I should add the light is very random and sometimes fades on and off. I replaced the brake master cylinder because it's 20 years old, still comes on. The worst of it is, it disables the cruise control when on. Harness?
 

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I have an intermittent brake warning light issue for a few months now. Disconnected the emergency brake switch and tested; switch is good and light still comes on with it disconnected. I should add the light is very random and sometimes fades on and off. I replaced the brake master cylinder because it's 20 years old, still comes on. The worst of it is, it disables the cruise control when on. Harness?
Check the ground

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Discussion Starter #3
Ah, which one? Grounding is how the system powers the brake problem light.
 

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Discussion Starter #4 (Edited)
I tested the switches on the NEW master cylinder too; light is still coming on. I have heard of the float sticking, I was hoping it was that. That is the main reason I replaced the original master cylinder

What about the vacuum pump or switch?
 

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Discussion Starter #6
The low vacuum switch is bad. I checked the system with my old vacuum gauge and it's showing ~23 inches plus gauge error. I also checked about 45 minutes later and it still had ~23 inches. I would think the switch is a discontinued item? Has anyone found a replacement or repaired the original switch?
 
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