2 questions

[laserjock]

1. What is this? It's on the pass inner fender?looks like a vacuum switch.

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2. My wiring harness is all hacked up. Can I swap it with a non-cruise truck? Looks like the cruise has its own wiring through the firewall.

Thanks!




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[riotwarrior]

low vacuum warning IIRC

 

[franklin2]

I am not sure in 91, but I know the older trucks has different horn wiring if they did not have cruise. If you did not have cruise, you had no horn relay, the full current of the horn went up through the steering wheel switch and back out to the horn. If you did have cruise, then they added a horn relay and a single wire going up the steering column which got grounded out to activate the relay, which then sent power to the horn.

See if you can find a diagram for your truck and compare that particular circuit. They may have stopped doing it that way, but 86-dwn are wired like that.

 

[laserjock]

Thanks!! So as far as I can tell, the steering column was replaced at some point for some reason. It has a non-tilt cruise column in it now which may explain why none of the electrical stuff works right. All kinds of electrical ugly in this thing. Ill see if I can dig up a schematic.

Thanks!


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[icanfixall]

That is the low vacuum switch that tells you the vacuum has failed for some reason. A lite comes on at the dash saying ...VACUUM...

 

[laserjock]

Well. I question it's current operating state given the number of holes I've found in the vacuum system.




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[icanfixall]

Not to worry. Most of these tuna cans don't operate any more. Mine sure has not worked in years but.. I have the hydroboost brake system. No vacuum needed for the power brakes. I get my boost from the power steering pump. Hydroboost is found on chvey trucks from 1979 that I know of and now it found on many new mustangs and other vans and cars. Its a much better power brake system..

 

[franklin2]

I believe my 89 turns on the "brake" light when that switch closes or opens, whatever it does.

 

[laserjock]

Gary, do you know of anyone running a mustang hydroboost? They seem to be plentiful. If they produce enough pressure, I don't see what would make the difference as long as you run the big master cylinder.


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[icanfixall]

My only concern is the mounting plate. Even if its the wrong bolt placement you can drill the firewall to make it fit. GM had them on the 1979 chevy trucks too but those mount plates wont fit ours. I believe the mounting plates are available thru Ford and international. Might get one from ABS Power Brake Inc in Orange Ca. There web site is www.abspowerbrake.com
I have bought from them in the past several times. They do fine street rod brake modification brake work.

 

[jrad235]

Not to worry. Most of these tuna cans don't operate any more. Mine sure has not worked in years but.. I have the hydroboost brake system. No vacuum needed for the power brakes. I get my boost from the power steering pump. Hydroboost is found on chvey trucks from 1979 that I know of and now it found on many new mustangs and other vans and cars. Its a much better power brake system..

I was actually wondering about that valve myself when I was on the trip to Vegas because it was in the way of the air intake I used(temporarily).

Hydro boost sounds great, if my power steering system didn't leak like a sieve.