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Steve
Steve, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 6833
Experience:  30+ yrs. experience, MMI, HD technician, HD early, engine rebuild/performance, bike builder, kit bike program manager, CCI 2001-2004
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Name is ***** *****. I have 88 softail fxst, and it was

Customer Question

Name is ***** *****. I have 88 softail fxst, and it was customized--not by me--so there are no turn signals and no key necessary for starting. Two problems, the primary being the brake lights work with break engagement but not otherwise. I was trying to get the speedo light to work, but can't figure it out. Bulb works, harness has continuity, but only one lead. And I think I shorted something out as bike won't turn over now. Are there fuses I may have blown?
JA: Thanks. Can you give me any more details about your issue?
Customer: when i was fastening the ignition metal housing to the bike, there was a spark, as it serves as a ground I guess, and now bike won't start
JA: OK got it. Last thing — Motorcycle Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 9 months ago.
Category: Motorcycle
Expert:  Steve replied 9 months ago.

"the brake lights work with break engagement but not otherwise" - that is correct operation.

- speedo light has +12v wire. circuit is completed by light fixture ground. if 12v is available from lighting circuit and bulb is grounded, bulb should function.

- 1988 Harley's have no fuses. they have circuit breakers which reset automatically when the short is removed.

let me know if you need more help.

Steve

Customer: replied 9 months ago.
Ok, I'm starting to get it. So the speedo bulb has one lead, I left it connected to where it was on the breaker. Is the other side of the breaker the ground? If so, then I have bad ground somewhere coming out of that terminal?More importantly, now that I've F'ed with it. I decided to shitcan the damn speed bulb and put it back to gether, but as soon as I screw the mount plate down--the one to which the ignition is mounted--I get some sparking. I disconnected negative at battery and tried to find any shorts. If the mount is loose, bike starts up, nothing different than before. But soon as I fasten that mount down it goes dead. Interesting side note--at least to me--when I checked neg terminal of battery to what I expected to be negative post on the handle bars I got 12V reading. a picture would probably help. can we do that?
Expert:  Steve replied 9 months ago.

no. the wire gong to the speedo bulb is a hot 12v when he ignition switch is in LIGHTS or IGNITION. the speedo mount is grounded and provides the ground to the bulb.

as for your other issue......you have a bad ground from the battery. it's either a bad cable or a bad connection.

let me know if you need more help.

Steve

Customer: replied 9 months ago.
I suspected the mount was the ground and that's why I wasn't getting it to light up because the mount wasn't seated--no ground. but now that I reseated the mount, nothing wants to work, I hear clicking near the battery area. Here are some photos. There are three random wires that used to be wired together, no affect that I could tell. But I've figured one of the blacks goes to the yellow terminal, the other black goes to the top left dashlight but what it's for has worn off. The blue one goes to a terminal on the breaker and I believe that where the speedo bulb was hooked. What do you think I fouled up as far as now the lights won't go on in ignition position and won't turn over?
Expert:  Steve replied 9 months ago.

the clicking in he battery area is the MAIN CIRCUIT BREAKER.

the circuit breakers on your bike are thermal circuit breakers. when they sense a overload, they get hot and trip open, breaking the circuit. after they cool, the automatically reset. if the overload is still present, the trip again, etc.

you have something shorted to ground. it is tripping the main circuit breaker.

the other breakers are under your dash......ign, lts, accy.

here is a link to a wiring diagram that is pretty close to your model and year (can't find an exact match)

http://www.officialharleyparts.com/harley/1991-93_flstc_919.jpg

let me know if you need more help.

Steve