North American Turbocoupe Organization

PRC switch
86XR7auto Offline
Hello All.....its been awhile....

Im still playing with TC's, but not really trying to go fast...well, not right now.

I have an 87 and 88TC with the same problem. Both have under 100k on them. The PRC's work, but only when you go to WOT, or go really fast. If you have the switch on out of 10 starts will get you firm light on. Is the switch bad? The Firm light on the dash doesnt flash like when you remove the PRC system or IRCM is bad.. The 87 has a vacuum conversion and 88 has the stock system with the ABS offline...IM shocked.

Thanks Guys,

86XR7 in pieces...old time [email protected] 88TC stock Red RHSC [email protected], 01 Z71=Nice winter ride, 01 CVLX w/HPP wifes ride!

Jeff K Offline
Good chance it is the switch. You can try spraying into it with electrical contact cleaner and working it back and forth. If that doesn't work, you can remove the switch panel and take the switch apart and clean it out.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized

86XR7auto Offline
Thanks Jeff....I have lots of electronic contact cleaner and lube...LOL...Ill give it a try.

86XR7 in pieces...old time [email protected] 88TC stock Red RHSC [email protected], 01 Z71=Nice winter ride, 01 CVLX w/HPP wifes ride!

anasazi4st Offline
Senior Member
You can also get in the trunk under the "package shelf" on the right side...lower that panel and you'll find the PRC unit (on the right I believe) next to the ABS one. There's two relays attached there, one each for the front and rear, respectively.

I was having all kinds of trouble with my PRC--often wouldn't come out of Firm ride, either by working the switch or from automatic use. I went through Actuators (the thing on top of each shock) like crazy and a couple of dashboard switches before I was able to figure out the REAL problem: the relays needed cleaned.

The plastic top comes off (remove it carefully and you'll be able to reuse it without GOOPing it back on). Spray the relay inside with electronic parts cleaner...mine were so bad I first touched them up with fine grit sandpaper, then eventually replaced them.

NAPA's part # is MPE AR243SB. In October 2013 they were $18 each, dunno about now. You should have no problem finding the relays at lots of other places, though. It's just a simple 2 position, three contact relay.

You might try this if nothing else seems to work.

Hope this helps.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 3 T5OD full rebuilds, 6 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....

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