• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)
Tips
Tips

Strange A/C - radio problem

70herald

Luke Skywalker
Country flag
Offline
My oldish nissan van has developed a strange problem. every time the A/C compressor kicks in (A/C clutch of course), the radio is re-starting. Now this isn't to shocking since the voltage is also dropping down to about 10v for a second and then coming back to around 13v.

any ideas welcome...
 

NutmegCT

Great Pumpkin
Silver
Online
Hi Yisrael. How old is "oldish"?

If the a/c compressor needs some lubrication, there could be an excess draw of current as the clutch kicks in.

And if the radio is an older digital system, a voltage drop could certainly "re-boot" the radio.

Just a thought.
Tom M.
 
OP
7

70herald

Luke Skywalker
Country flag
Offline
"oldish" would be 14 in this case (yeah I know for a site dealing mostly with LBCs this isn't really old) The radio is probably old enough to be called "oldish" also.

You are talking about oil in the compressor? not some sort of lubrication of the clutch?
Yisrael
 
D

Deleted member 8987

Guest
Guest
Offline
If the AC clutch engaging drops voltage to 10, well, something else down the line is bad. The clutch fuse would blow or the clutch relay would smoke. You have a voltage feed issue, positive or ground. Where is the voltage measured when it drops to 10V?
Load test the battery, check the alternator output, voltage drop across cables under load, that kind of stuff.
 
D

Deleted member 8987

Guest
Guest
Offline
No activity.

E=IxR.

If locked, your belt would squeal. Excessive load, same. Your clutch fuse would blow.
Compressors are oiled once, then when you open and drain the system, do it again. No dipstick.

10V where? Engine has to be running to engage A/C, so if 10V at battery, you have a charging system problem.

Do your headlights draw it down? Again, where are you measuring the 10V?

The battery will provide enough power to arc weld. Dirty cables? Still, 14+ off the alternator, not 13. Load like I said would blow the fuse if enough to drop three volts, E-IxR.

The more I think about this, especially since I had a clutch coil go bad this year....the maximum current to the clutch is small. Windings are small. Just enough to pull the plate in on compressor shaft (my winding opened when it got real hot outside...corrected when cold).

I think your alternator has a problem. Or the idle kick for the AC isn't working.

The load when the mechanical AC starts (not electrical) slows the engine down, drops your 13v charge off....and battery is probably shot, too (or not even getting enough charge) to not hold voltage up when the charge effectively goes away when idle drops.
 
OP
7

70herald

Luke Skywalker
Country flag
Offline
I think you are on the correct track. If I recall correctly, I measures + on the battery and - on chassis so any resistance would have been measured.
Unfortunately I have been dealing with my own problems instead of the cars problems.. but will get back to this very soon since it has gotten hot out again.

This is a nice torquey diesel and doesn't seem to have any problem keeping idle speed up, and the alternator is on a different belt so it slipping shouldn't be an issue.

The other issue that may be is the big radiator fans (it has 2) but I think problem there big enough to drop voltage would blow the fuse.

I think the first thing I need to do is go back and remeasure voltage at battery and then start tracing the wiring. I think you are 100% on with a bad connection somewhere.
Thanks
Yisrael
 
OP
7

70herald

Luke Skywalker
Country flag
Offline
Problem found! and as predicted by TOC a voltage feed issue. The bolt holding the ground cable to the chassis was rusty, loose and impossible to get at.
I guess I could have tried tightening it if I took out the radiator and more stuff. Just broke off the old bolt and found a new mounting place for the cable. Kind of surprised it worked at all. that cable connector was just flapping around. Must have sent out a stream of sparks every time we started the engine.
Checked voltages both at battery and a few other locations, voltage is now at ~13.5 at idle with EVERYTHING on.. Radio no longer resets itself.
 
Last edited:
Similar threads
Thread starter Title Forum Replies Date
Vargus TR2/3/3A Strange dents Triumph 19
nicko Strange Engine Noise Austin Healey 7
jlaird MGB Strange daily question. MG 10
C MGB strange?? MG 3
J TR2/3/3A such strange thread on gear shift knob Triumph 12
S TR2/3/3A Strange part Triumph 3
steveg Strange gasket pieces Austin Healey 5
steveg Strange Oil Leak Austin Healey 7
D TR2/3/3A Strange hole! Triumph 5
SherpaPilot Strange Noise While Cornering in TR6 Racing 3
Jim_Gruber Strange noises - Bad U Joint perhaps? Spridgets 10
Michael Oritt Strange debris found in sump Austin Healey 19
F TR2/3/3A Strange Loud Noise Triumph 11
C Strange...can won't start and then magically ressurects Austin Healey 16
bighealeysource Strange problem with throttle staying open Austin Healey 6
D TR2/3/3A Strange Transmission Issue Triumph 9
Rhodyspit75 Strange windshield washers Spridgets 0
tahoe healey strange OD question. Austin Healey 9
andrea Very strange austin healey 3.9 Austin Healey 5
M Strange Healey Tach Austin Healey 9
Rut Strange occurance! Spridgets 19
aeronca65t Big Healey-strange wheels Austin Healey 12
bighealeysource Okay, here's one with a strange noise from the engine Austin Healey 7
J TR2/3/3A Strange fiberboard panel behind rear seat in TR3 Triumph 10
J TR4/4A Strange question that may involve the coil- Triumph 13
jlaird Todays strange question Spridgets 6
JPSmit What is that strange grinding sound in the distance? Spridgets 3
PAUL161 MGB Strange Reminder of a Missing Friend. MG 4
B Strange rear light Other British Cars 6
KVH Strange Sound Like Compressed Air Escaping Triumph 14
Bremer TR2/3/3A TR3A: Strange brake bleeding behaviour Triumph 4
B SU Carbs have strange vacuum fitting Triumph 17
Kleykamp TR2/3/3A Strange TR3 side curtains ??? Triumph 13
HAN8L1965 Strange event ? Spridgets 6
T strange litter Triumph 5
aeronca65t Strange and interesting MGs MG 3
PAUL161 Strange 5 Speed Conversion - Will it Work? MG 41
W Strange occurence Spridgets 5
P Strange clunking noise Triumph 20
bugedd Strange trans noise Spridgets 7
Musicman Strange Clicky/Tappy Sound Triumph 6
SilentUnicorn Strange things British Motorbikes 4
Bremer Strange, but interesting... factory blunders? Triumph 8
M another strange bugeye on ebay Spridgets 12
JAV strange noise Austin Healey 4
J Strange electric problem. Jaguar 11
racingenglishcars This is a strange one! Spridgets 9
A I noticed something strange FORUM Help 4
G Strange Engine Noise...? Austin Healey 20
bcliff Strange rumble/hum MG 13

Similar threads

Top