I have a '91 LS400 that I was recently performing some power steering system repairs on. Last night I got everything back together, cranked it up for a road test, and found that while the car started just fine, the dash lights, power windows, tail lights, etc. were not operating. The shift lever was also locked in Park. I checked all the fuses and relays, but could not find anything obviously amiss.

Thoroughly frustrated at this point, I sat in the car repeatedly starting and shutting it down when for some unknown reason I decided to rev it a bit. Lo and behold, at some midrange rev count, the lights came on and everything else with it. I thought somehow something just fell into place, but no. The problem occurs every time the car is started.

Anyone have any ideas?

 

Sounds like a low voltage situation.

 

Any ideas on what and where I should check?

Why would eveything seem to remain okay for the duration of the time the car was running, even with lights and other accessories on?

Is there anything that I could possibly have bumped or otherwise have loosened while working on P/S system?

Questions, questions, questions...

Thanks.

 

check alternator, common problem for them to fail from getting PS fluid dripped on them from a leaky/dead PS pump.

also check alternator ground and the battery/alt connections.

 

Don't think the alternator was damaged by fluid. I did, however, loosen a nut on the alternator to swing a wire out of the way so that I could access the vacuum valve for removal. I think that I retightened it OK, but I'll check it tomorrow. Maybe clean it as well. Any other suggestions while I'm fooling with it?

Need to call it a night for now (get up for work in 4.25 hours).

I'll keep anyone who is interested posted on this tomorrow afternoon/evening after I have a chance to follow up on the suggestions.

Thanks.

 

May suggest you place a digital volt meter across the battery and give us these readings:

- Before start
- Started, at idle
- Engine accellerated to 2000 RPM
- Engine back to idle

 

I have been at work for the last several hours, and have not had an opportunity to check this thread until now, It will be another 5 hours (5:00 pm CST) before I'm able to get back to the car. I'll post the data from the readings that Tammy suggested at that time.

Meanwhile, thanks for the feedback everyone.

 

I finally have a chance to see if I can solve this problem (with everyone's very gracious help).

So far, all I have done is take the voltage readings as per Tammy's advice.

Engine off: 12.24v
Idle: 11.81v
2000rpm 11.74v
Idle again: 11.74v

I'm going to check the wires and connections at the alternator now. They are the only electrical components that I had any contat with while workin on the P/S. I'll post my findings.

Any other suggestions are, as always, welcome.

Thanks.

 

This is the voltages you are looking for....

Engine off: 12.8v
Idle: 14.2v
2000RPM: 14.3v
Idle again 14.0v

Your alternator should be checked for possible worn brushes or malfunctioning voltage regulator.

 

Yeah, I figured from the readings that the alternator wasn't putting out. Still have a hard time believing that the sudden failure is due to something that occurred when I was working on the P/S. I checked the connections at the alternator and the ground--seems OK.

I did come across something interesting though. I pulled up the wiring diagram, and it shows 2 wires from the alternator running through a 120A fusible link located in what the diagram labels as the "FUSIBLE LINK BOX". I couldn't find such a box, but I was looking in the underhood fuse box and noticed that there is a 120A "cartridge fuse" (as the Lexus handbook refers to it). I also noticed that said fuse is cooked. Anybody know if this may be my problem? Also, how do I remove the thing?

Help...and thanks.

 

I had to change that in my 91 LS about a year ago. If I recall, the fuse is held in by a screw which must be loosened from the side. I believe there is a plastic cover which must be removed to gain access to the screw. This is all by memory. I do remember that it wasn't very difficult to do. Once I removed the fuse, I was able to get a replacement at my local auto parts store.

 

I finally got back to the LS this afternoon. Stopped at the dealer for an expensive ($12.40) 120A cartridge fuse/fusible link. The only problem I had installing it was separating the small fusible link block from the main engine compartment fuse box in order to access the second (10mm) hex bolt. The fuse is locked in by 2 bolts--the other easy to access one is 8mm. If anyone has an easy way to do this, I wish they would post it. A search of the forums didn't yield much.

Anyway, thanks to everyone who posted suggestions, everything seems to be fine now (except I need to find the instructions for resetting the air bag warning lamp, which came on when I reattached the battery cable).

P.S.--Thanks for putting up with my newbiness also.