Longhaul

I've spent about an hour searching for this and have consulted the manual. Before I started tearing into the car, I am hoping that maybe someone else has dealt with this.

The car is an 88 convertible in great condition. I have a rebuilt motor in it with only 40k miles on it. The only other electrical issue that I believe exists is that the alarm does not seem to work.

What's happening: The top goes up, but will not go down! It started as an intermittent problem that was at best annoying, but now it is intolerable!

I pull the e-brake, put the car in neutral, foot on the brake, and turn the ****. Nothing happens. I can turn towards closing and the motors try to close a little bit more.

The light for the e-brake on the dash comes on when the lever is pulled, and goes off when it is not, so I think that is not the issue.

Has anyone bypassed the safety stuff on the top? I used to have another 88 vert that I drove back from CA to GA that would go up or down at the twist of the switch. It didn't even stop short of closing.

The only other thread I've found on this recommends that the motors be disengaged and that is not what I would like to do.

Thanks

magus2222

iTrader: (22)

unless i am mistaken, the top does not rely on the parking brake being engaged, the foot brake being engaged, nor the clutch.
it sounds like your motors are failing/have already failed. the top motors work a lot like the window motors, where it reverses the electrical polarity to make the arms change direction...again, may be wrong as im not an expert on the vert top
anyways, if the top goes up, bot wont go down: either your motors are failing internally, or the electrical is failing internally, either way, test the motors with a dvom as it states in the fsm, but you may need another person to assist you on this. while an assistant holds the switch to activate the top, test the motor as per the fsm.
past that? just replace the motors. there are a lot of them floating around, and i personally have 2 sets of the for sale lol

edit: also, check the switch, it may not be sending a signal to the motors themselves

Lloyd

Longhaul

The attached picture is the electrical diagram for the 88 vert.

From looking at the Convertible Top Switch block, it seems to imply that the right motor has the convertible top control unit housed with it?

There is also a "CHECK CONNECTOR" box that gets a power, ground, a signal from the parking brake switch, and signal from the "CONVERTIBLE TOP SWITCH" for both the CLOSE and OPEN position. The last two signals are also connected to what looks to be limit switches.

From the looks of the MOTOR block, there is a relay that is activated that either turns the motor in one direction or the other. However, this is difficult to determine because the coils in the relays are both activated by the same signal that comes out of the MOTOR block REGULATOR.

I am an electrical engineer, used to looking at schematics for WMDs, not 23 year old foreign cars, so I am most likely interpreting a few things wrong.

Given the intermittent (although lately not so much) nature of this problem, I'm guessing that this could potentially be a stuck limit switch or a connector problem.

SURELY someone out there has had this same problem?

magus2222

iTrader: (22)

hm, maybe s4 and s5 are different, as i can operate mine without the ebrake or the footbrake. these have a tendancy to fail internally, so just test them with a dvom

Lloyd

Longhaul

I'm 90% certain that the parking brake has to be pulled. It shows up on all the schematics. It even goes to the "CHECK CONNECTOR"

I'm going to try looking at the signals at this connector. This connector, if I can find it, is in the engine compartment on the passenger side about 1/2 way back from the front. It has the brake signal, OPEN, CLOSE, power, and ground. I'll be able to tell if the switch and brake signals are working from there. If the OPEN signal does not go high, then it is either the switch or the harness. I think I would rather it be the harness! No telling how much a switch would cost!

Of course, it will not be something so easy. I'm sure I will have to tear into the back area and start looking at the connectors to the motors. I think I can get to those by taking off the back cover to the spare. Hopefully I can narrow it down to a limit switch. Then I'll just remove it

Longhaul

Things got weird from 88 to 89. The wiring is way different. I don't think it was until 90 that the they actually showed up right in the FSM. I did a V8 conversion on an 89 and the wiring info in the FSM was not always right. Sometimes I had to look at the 88 FSM, sometimes the 89, and sometimes the 90 to get wiring that matched what was in my car! What a PITA!

magus2222

iTrader: (22)

wow, theres a reason i just replace **** instead of troubleshooting it with these cars hahaha

Lloyd

HOZZMANRX7

iTrader: (43)

As the owner of three verts, I'm 100% certain the hand brake needs to be pulled up to either raise OR lower the top.

My bet, the contact in your switch are simply dirty since it works up telling the top to go up but not down. So clearly the power circuit to the switch is good as well as from the switch. The top switch is a simple A/B type.

Proplem is, since the top switch in an '88 is in the wiper switch module, it's a real PITA to pull apart so you can clean the contacts. But, that's what you have to do unless you re-wire it to an S5 switch that mounts in the center console.